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diff --git a/challenge-328/barroff/raku/ch-1.p6 b/challenge-328/barroff/raku/ch-1.p6
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+++ b/challenge-328/barroff/raku/ch-1.p6
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+#!/usr/bin/env raku
+
+use v6.d;
+
+sub replace-all-q(Str $str --> Str) {
+    return $str unless $str.contains('?');
+    my @chars = $str.comb;
+    if @chars[0] eq '?' {
+        @chars[0] = @chars[1] eq 'a' ??  'b' !! 'a';
+    }
+    for 1..@chars.elems - 2 {
+        if @chars[$_] eq '?' {
+            my $surroundings = Set(@chars[$_ - 1], @chars[$_ + 1]);
+            if 'a' ∉ $surroundings {
+                @chars[$_] = 'a';
+            } elsif 'b' ∉ $surroundings {
+                @chars[$_] = 'b';
+            } else {
+                @chars[$_] = 'c';
+            }
+        }
+    }
+    @chars.join;
+}
+
+#| Run test cases
+multi sub MAIN('test') {
+    use Test;
+    plan 3;
+
+    is replace-all-q("a?z"), "abz", 'works for "a?z"';
+    is replace-all-q("pe?k"), "peak", 'works for "pe?k"';
+    is replace-all-q("gra?te"), "grabte", 'works for "gra?te"';
+}
+
+#| Take user provided string like "a?z"
+multi sub MAIN(Str $str) {
+    say replace-all-q($str);
+}