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diff --git a/challenge-039/paulo-custodio/python/ch-2.py b/challenge-039/paulo-custodio/python/ch-2.py
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+++ b/challenge-039/paulo-custodio/python/ch-2.py
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+#!/usr/bin/env python3
+
+# Challenge 039
+#
+# TASK #2
+# Contributed by Andrezgz
+# Write a script to demonstrate Reverse Polish notation(RPN). Checkout the wiki
+# page for more information about RPN.
+
+import sys
+
+# simple rpn calculator
+stack = []
+
+def rpn(op):
+    if op.isdigit():
+        stack.append(int(op))
+    elif op == '+':
+        b = stack.pop()
+        a = stack.pop()
+        stack.append(a+b)
+    elif op == '-':
+        b = stack.pop()
+        a = stack.pop()
+        stack.append(a-b)
+    elif op == '*':
+        b = stack.pop()
+        a = stack.pop()
+        stack.append(a*b)
+    elif op == '/':
+        b = stack.pop()
+        a = stack.pop()
+        stack.append(a/b)
+    elif op == '.':
+        a = stack.pop()
+        print(a)
+    elif op.isspace():
+        pass
+    else:
+        print("invalid operation:", op)
+
+for c in "".join(sys.argv[1:]):
+    rpn(c)