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

$s = str_split(trim(fgets(STDIN)));
$t = str_split(trim(fgets(STDIN)));

$tmp_s = $s;
sort($tmp_s);

$tmp_t = $t;
sort($tmp_t);

foreach($tmp_t as $v) {
	if(!in_array($v, $tmp_s, true)) {
		echo "-1\n";
		return;
	}
}

$i = 0;
$count = 0;
$flag = 0;
$idx = 0;
while(1) {
	foreach($s as $v) {
		$count++;
		
		if($t[$i] === $v) {
			$idx = $count - 1;
			$i++;
		}

		if(count($t) === $i) {
			$flag = 1;
		 	break;
		}

		if($count > $idx + count($s)) {
			echo "-1\n";
			return;
		}
	}

	if($flag === 1) break;

	if($count === 1000) break;
}

if($count === 1000) {
	echo "-1\n";
	return;
}

echo $count."\n";