Update 322_coin_change.md

Author: Joseph Luce

leetcode/medium/322_coin_change.md

@@ -12,7 +12,7 @@ We can build the minimum coins as we increase the amount by using the previous c
 For example, if you have an input of [1,5,7] coins.
 The minimum coins for amount 1 and 5 is 1. 
 When we get to amount 6 with coin 5, we will look at amount 1 (6-5=1) for its minimum coin, which is 1 and do 1+1 at amount 6.
-Similarly, when we get to amount 13 with coin 7, we do 13-7=6, look at amount 6 which is 2 minimum coins and do 2+1 for amount 12.
+Similarly, when we get to amount 13 with coin 7, we do 13-7=6, look at amount 6 which is 2 minimum coins and do 2+1 for amount 13.
 We repeat this until we reach the given amount.
 
 We can do some further optimizations by removing coins that are over the given amount.