CF523C.Name Quest

A Martian boy is named s — he has got this name quite recently from his parents for his coming of age birthday. Now he enjoys looking for his name everywhere. If he sees that he can obtain his name from some string by removing zero or more letters (at that, the remaining letters remain in the same order), he gets happy. For example, if s=«aba», then strings «baobab», «aabbaa», «helloabahello» make him very happy and strings «aab», «baaa» and «helloabhello» do not.

However rather than being happy once, he loves twice as much being happy twice! So, when he got string t as a present, he wanted to cut it in two parts (the left part and the right part) so that each part made him happy.

Help s determine the number of distinct ways to cut the given string t into two parts in the required manner.

一位火星男孩的名字是 s —— 这个名字是他父母为庆祝他成年生日而刚刚为他取的。现在，他热衷于在各处寻找自己的名字。如果他发现可以从某个字符串中通过删除零个或多个字母（剩余字母保持原有顺序）得到自己的名字 s，他就会感到开心。例如，若 s = «aba»，则字符串 «baobab»、«aabbaa»、«helloabahello» 会让他非常开心；而字符串 «aab»、«baaa» 和 «helloabhello» 则不会。

然而，他并不满足于仅仅开心一次，而是更喜欢开心两次！因此，当他收到字符串 t 作为礼物时，他希望将其切成两部分（左部分和右部分），使得每一部分都能让他开心。

请帮助 s 确定将给定字符串 t 按上述要求切成两部分的不同方式的数量。

The first line contains string s, consisting of lowercase English letters. The length of string s is from 1 to 1000 letters.

The second line contains string t, that also consists of lowercase English letters. The length of string t is from 1 to 106 letters.

第一行包含字符串 $s$，由小写英文字母组成。字符串 $s$ 的长度为 $1$ 至 $1000$ 个字母。

第二行包含字符串 $t$，同样由小写英文字母组成。字符串 $t$ 的长度为 $1$ 至 $10^6$ 个字母。

Print the sought number of ways to cut string t in two so that each part made s happy.

输出将字符串 $t$ 切分为两部分的方式数（使得每一部分都使 $s$ 满足“快乐”条件）。