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 Java8 (OpenJDK 1.8.0) (judge verdict: Time Limit Exceeded)

import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Silviase
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        EStringsofImpurity solver = new EStringsofImpurity();
        solver.solve(1, in, out);
        out.close();
    }

    static class EStringsofImpurity {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            String s = in.next();
            String t = in.next();
            int[][] next = new int[s.length()][26];
            long res = 0;
            int num = 0;
            // next[i][j]: sのi文字目以降で何文字先にj(alphabet)が現れるか.
            // 現れなければ-1;
            StringBuilder sb = new StringBuilder(s);
            sb.append(s);
            String ss = new String(sb);
            for (int i = 0; i < s.length(); i++) {
                for (int j = 0; j < 26; j++) {
                    char alphabet = (char) ('a' + j);
                    if (t.indexOf(alphabet) == -1) {
                        continue;
                    }
                    next[i][j] = ss.indexOf(alphabet, i) - i;
                }
            }


            for (int i = 0; i < t.length(); i++) {
                char t_i = t.charAt(i);
                if (next[num % s.length()][t_i - 'a'] < 0) {
                    res = -1;
                    break;
                }
                res += next[num % s.length()][t_i - 'a'] + 1;
                num = (int) (res % s.length());
                // out.println(res);
            }

            out.println(res);

        }

    }
}