7 files changed, 153 insertions, 2 deletions
diff --git a/challenge-277/sgreen/README.md b/challenge-277/sgreen/README.md
index 621adc8383..8bd32e6a72 100644
--- a/challenge-277/sgreen/README.md
+++ b/challenge-277/sgreen/README.md
@@ -1,3 +1,3 @@
-# The Weekly Challenge 276
+# The Weekly Challenge 277
 
-Blog: [Complete frequency](https://dev.to/simongreennet/complete-frequency-2fke)
+Blog: [Strong counting](https://dev.to/simongreennet/strong-counting-10on)
diff --git a/challenge-277/sgreen/blog.txt b/challenge-277/sgreen/blog.txt
new file mode 100644
index 0000000000..0fae17fa75
--- /dev/null
+++ b/challenge-277/sgreen/blog.txt
@@ -0,0 +1 @@
+https://dev.to/simongreennet/strong-counting-10on
+\ No newline at end of file
diff --git a/challenge-277/sgreen/perl/ch-1.pl b/challenge-277/sgreen/perl/ch-1.pl
new file mode 100755
index 0000000000..52a759c9b5
--- /dev/null
+++ b/challenge-277/sgreen/perl/ch-1.pl
@@ -0,0 +1,33 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature 'say';
+use experimental 'signatures';
+
+use List::Util 'uniq';
+
+sub main (@words) {
+    my @words_list = map { [split / / ]} @words;
+    my $count      = 0;
+
+    # Take a list of unique words in the first list
+  O: foreach my $word ( uniq( @{ $words_list[0] } ) ) {
+        # Check that it occurs once in each list
+        foreach my $words (@words_list) {
+            my $c = grep { $_ eq $word } @$words;
+            if ( $c != 1 ) {
+                # It doesn't, go to the next word.
+                next O;
+            }
+        }
+
+        # It does, add to the count
+        $count++;
+    }
+
+    # Count the number of words that appear in all lists
+    say $count;
+}
+
+main(@ARGV);
+\ No newline at end of file
diff --git a/challenge-277/sgreen/perl/ch-2.pl b/challenge-277/sgreen/perl/ch-2.pl
new file mode 100755
index 0000000000..a8d366207b
--- /dev/null
+++ b/challenge-277/sgreen/perl/ch-2.pl
@@ -0,0 +1,26 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use feature 'say';
+use experimental 'signatures';
+
+use List::Util qw(min uniq);
+
+sub main (@ints) {
+    # Remove duplicates
+    @ints = uniq(@ints);
+    my $count = 0;
+
+    foreach my $i ( 0 .. $#ints - 1 ) {
+        foreach my $j ( $i + 1 .. $#ints ) {
+            if ( abs( $ints[$i] - $ints[$j] ) < min( $ints[$i], $ints[$j] ) ) {
+                $count++;
+            }
+        }
+    }
+
+    say $count;
+}
+
+main(@ARGV);
+\ No newline at end of file
diff --git a/challenge-277/sgreen/python/ch-1.py b/challenge-277/sgreen/python/ch-1.py
new file mode 100755
index 0000000000..0338922088
--- /dev/null
+++ b/challenge-277/sgreen/python/ch-1.py
@@ -0,0 +1,32 @@
+#!/usr/bin/env python3
+
+from collections import Counter
+import sys
+
+
+def count_common(*words_list: list[list]) -> int:
+    count = 0
+
+    # Take a list of unique words in the first list
+    for word in set(words_list[0]):
+        # Check that it occurs once in each list
+        for words in words_list:
+            if words.count(word) != 1:
+                # It doesn't, go to the next word.
+                break
+        else:
+            # It does, add to the count
+            count+=1
+
+    # Count the number of words that appear in all lists
+    return count
+
+def main():
+    # Convert two space-separated strings into muliple lists
+    word_list = (words.split(' ')for words in sys.argv[1:])
+    result = count_common(*word_list)
+    print(result)
+
+
+if __name__ == '__main__':
+    main()
diff --git a/challenge-277/sgreen/python/ch-2.py b/challenge-277/sgreen/python/ch-2.py
new file mode 100755
index 0000000000..7896268051
--- /dev/null
+++ b/challenge-277/sgreen/python/ch-2.py
@@ -0,0 +1,27 @@
+#!/usr/bin/env python3
+
+import sys
+
+
+def strong_pair(ints: list) -> int:
+    # Remove duplicates
+    ints = list(set(ints))
+    count = 0
+
+    for i in range(len(ints)-1):
+        for j in range(i+1, len(ints)):
+            if abs(ints[i]-ints[j]) < min(ints[i], ints[j]):
+                count += 1
+
+    return count
+
+
+def main():
+    # Convert input into integers
+    array = [int(n) for n in sys.argv[1:]]
+    result = strong_pair(array)
+    print(result)
+
+
+if __name__ == '__main__':
+    main()
diff --git a/challenge-277/sgreen/python/test.py b/challenge-277/sgreen/python/test.py
new file mode 100755
index 0000000000..fd5e90dbf2
--- /dev/null
+++ b/challenge-277/sgreen/python/test.py
@@ -0,0 +1,32 @@
+#!/usr/bin/env python3
+
+import unittest
+ch_1 = __import__('ch-1')
+ch_2 = __import__('ch-2')
+
+
+class TestClass(unittest.TestCase):
+    def test_ch_1(self):
+        self.assertEqual(
+            ch_1.count_common(
+                ["Perl", "is", "my", "friend"],
+                ["Perl", "and", "Raku", "are", "friend"]),
+            2)
+        self.assertEqual(
+            ch_1.count_common(
+                ["Perl", "and", "Python", "are", "very", "similar"],
+                ["Python", "is", "top", "in", "guest", "languages"]),
+            1)
+        self.assertEqual(
+            ch_1.count_common(
+                ["Perl", "is", "imperative", "Lisp", "is", "functional"],
+                ["Crystal", "is", "similar", "to", "Ruby"]),
+            0)
+
+    def test_ch_2(self):
+        self.assertEqual(ch_2.strong_pair([1, 2, 3, 4, 5]), 4)
+        self.assertEqual(ch_2.strong_pair([5, 7, 1]), 1)
+
+
+if __name__ == '__main__':
+    unittest.main()