AT_abc393_a [ABC393A] Poisonous Oyster

There are four types of oysters, labeled $ 1 $ , $ 2 $ , $ 3 $ , and $ 4 $ . Exactly one of these types causes stomach trouble if eaten. The other types do not cause stomach trouble when eaten. Takahashi ate oysters $ 1 $ and $ 2 $ , and Aoki ate oysters $ 1 $ and $ 3 $ . The information on whether each person got sick is given as two strings $ S_1 $ and $ S_2 $ . Specifically, $ S_1 = $ `sick` means Takahashi got sick, and $ S_1 = $ `fine` means Takahashi did not get sick. Likewise, $ S_2 = $ `sick` means Aoki got sick, and $ S_2 = $ `fine` means Aoki did not get sick. Based on the given information, find which type of oyster causes stomach trouble.

The input is given from Standard Input in the following format: > $ S_1 $ $ S_2 $

Print the label of the oyster that causes stomach trouble if eaten.

### Sample Explanation 1 Takahashi (who ate oysters $ 1 $ and $ 2 $ ) got sick, and Aoki (who ate oysters $ 1 $ and $ 3 $ ) did not get sick, so it can be concluded that oyster $ 2 $ causes stomach trouble. ### Sample Explanation 2 Neither Takahashi (who ate oysters $ 1 $ and $ 2 $ ) nor Aoki (who ate oysters $ 1 $ and $ 3 $ ) got sick, so it can be concluded that oyster $ 4 $ causes stomach trouble. ### Constraints - Each of $ S_1 $ and $ S_2 $ is `sick` or `fine`.