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 C (GCC 5.4.1) (judge verdict: Runtime Error)

#include <stdio.h>

typedef struct {
    char sent[10000];
    long int len;
}string;

string scan(){
    string word;
    char c;
    int i = 0;
    while((c = getchar()) != '\n'){
        word.sent[i] = c;
        i++;
    }
    word.sent[i + 1] = '\0';
    word.len = i;
    return word;
}

int judge(string s, string t){
    int ans = 1, i, j;
    for(i = 0; i < t.len; i++){
        for(j = 0; j < s.len; j++){
            //printf("i=%d,j=%d", i, j);
            if(s.sent[j] == t.sent[i]){
                break;
            }else if(j + 1 == s.len){
                ans = 0;
            }
        }
        if(ans == 0){break;}
    }
    return ans;
}

void makeCountST(string s, string t){
    long int count = 0, p_t = 0, i;
    while(1){
        for(i = 0; i < s.len; i++){
            if(p_t == t.len){
                goto RESULT;
            }else if(s.sent[i] == t.sent[p_t]){
                p_t++;
            }
            count++;
        }
    }
    RESULT:
    printf("%ld", count);
}

int main(){
    string s, t;
    s = scan();
    t = scan();
    
    if(judge(s, t)){
        printf("s.len=%ld t.len=%d\n", s.len, t.len);
        makeCountST(s, t);
    }else{
        printf("-1");
    }
}