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diff --git a/python/031-coin_sums.py b/python/031-coin_sums.py
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+# ###
+# Coin sums
+# Problem 31
+# 
+# In England the currency is made up of pound, £, and pence, p, and there are eight coins in general circulation:
+# 1p, 2p, 5p, 10p, 20p, 50p, £1 (100p) and £2 (200p).
+# It is possible to make £2 in the following way:
+# 1×£1 + 1×50p + 2×20p + 1×5p + 1×2p + 3×1p
+# How many different ways can £2 be made using any number of coins?
+# ###
+
+
+coins = [200, 100, 50, 20, 10, 5, 2, 1]
+solutions = []
+
+def backtrack(n, sol):
+    if sum(sol) > n:
+        return
+    if n == 0:
+        solutions.append(sol)
+        return
+    while next_sol(n, sol):
+        backtrack(n, sol)
+
+def next_(n, sol):
+
+
+backtrack(10, [])