Problem:
Score : 500 points

Problem Statement

Given are two strings s and t consisting of lowercase English letters. Determine if there exists an integer i satisfying the following condition, and find the minimum such i if it exists.

Let s' be the concatenation of 10^{100} copies of s. t is a subsequence of the string {s'}_1{s'}_2\ldots{s'}_i (the first i characters in s').

Notes

A subsequence of a string a is a string obtained by deleting zero or more characters from a and concatenating the remaining characters without changing the relative order. For example, the subsequences of contest include net, c, and contest.

Constraints

1 \leq |s| \leq 10^5

1 \leq |t| \leq 10^5

s and t consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

s
t

Output

If there exists an integer i satisfying the following condition, print the minimum such i; otherwise, print -1.

Sample Input 1

contest
son

Sample Output 1

10

t = son is a subsequence of the string contestcon (the first 10 characters in s' = contestcontestcontest...), so i = 10 satisfies the condition.

On the other hand, t is not a subsequence of the string contestco (the first 9 characters in s'), so i = 9 does not satisfy the condition.

Similarly, any integer less than 9 does not satisfy the condition, either. Thus, the minimum integer i satisfying the condition is 10.

Sample Input 2

contest
programming

Sample Output 2

-1

t = programming is not a substring of s' = contestcontestcontest.... Thus, there is no integer i satisfying the condition.

Sample Input 3

contest
sentence

Sample Output 3

33

Note that the answer may not fit into a 32-bit integer type, though we cannot put such a case here.

Solution in PHP7 (7.0.15) (judge verdict: Wrong Answer)

<?php                                                                                                                                                          
                                                                                                                                                               
$str = trim(fgets(STDIN));                                                                                                                                     
$cnt = 0;                                                                                                                                                      
$prev = 0;                                                                                                                                                     
foreach (str_split(trim(fgets(STDIN))) as $p) {                                                                                                                
    $idx = strpos($str, $p, $prev);                                                                                                                            
    if ($idx === false) {                                                                                                                                      
        $cnt += strlen($cnt);                                                                                                                                  
        $idx = strpos($str, $p);                                                                                                                               
    }                                                                                                                                                          
    if ($idx === false) {                                                                                                                                      
        $cnt = -1;                                                                                                                                             
        break;                                                                                                                                                 
    }                                                                                                                                                          
    $prev = $idx;                                                                                                                                              
    $cnt += $idx + 1;                                                                                                                                          
    if ($cnt > 1000) {                                                                                                                                         
        $cnt = -1;                                                                                                                                             
        break;                                                                                                                                                 
    }                                                                                                                                                          
}                                                                                                                                                              
echo $cnt.PHP_EOL;