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 Python (3.4.3) (judge verdict: Time Limit Exceeded)

ss = {}
s = input()
sx = len(s)
t = input()
ff = True
for i in t:
    if i not in s:
        ff = False
        break
if ff:
    for i in range(0,len(s)):
        if s[i] not in ss:
            ss[s[i]] = [i]
        else:
            ss[s[i]].append(i)
    curr_len = ss[t[0]][0]
    curr_ind = ss[t[0]][0]
    for i in range(1,len(t)):
        x = t[i]
        f = False
        for i in range(0,len(ss[x])):
            if ss[x][i] > curr_ind:
                f = True
                curr_len += ss[x][i]-curr_ind
                curr_ind = ss[x][i]
                break
        if not f:
            curr_len += (sx - curr_ind)+ss[x][0]
            curr_ind = ss[x][0]
    print(curr_len+1)
else:
    print(-1)