Two Strings

2000ms

262144K

Description:

A subsequence of length |x| of string s = s₁s₂... s_|s| (where |s| is the length of string s) is a string x = s_k₁s_k₂... s_{k_|x|} (1 ≤ k₁ < k₂ < ... < k_|x| ≤ |s|).

You've got two strings — s and t. Let's consider all subsequences of string s, coinciding with string t. Is it true that each character of string s occurs in at least one of these subsequences? In other words, is it true that for all i (1 ≤ i ≤ |s|), there is such subsequence x = s_k₁s_k₂... s_{k_|x|} of string s, that x = t and for some j (1 ≤ j ≤ |x|) k_j = i.

Input:

The first line contains string s, the second line contains string t. Each line consists only of lowercase English letters. The given strings are non-empty, the length of each string does not exceed 2·10⁵.

Output:

Print "Yes" (without the quotes), if each character of the string s occurs in at least one of the described subsequences, or "No" (without the quotes) otherwise.

Sample Input:

abab
ab

Sample Output:

Yes

Sample Input:

abacaba
aba

Sample Output:

No

Sample Input:

abc
ba

Sample Output:

No

Note:

In the first sample string t can occur in the string s as a subsequence in three ways: abab, abab and abab. In these occurrences each character of string s occurs at least once.

In the second sample the 4-th character of the string s doesn't occur in any occurrence of string t.

In the third sample there is no occurrence of string t in string s.

Informação

Provedor Codeforces

Código CF223B