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 PyPy3 (2.4.0) (judge verdict: Accepted)

S = [ord(s) - 97 for s in input()]
T = [ord(t) - 97 for t in input()]
SS = S + S
ls = len(S)

indexes = [[] for _ in range(26)]
for i, s in enumerate(SS):
    indexes[s].append(i)
m = [[-1] * 26 for _ in range(2 * ls)]
for s in range(26):
    inds = [0] + indexes[s]
    for r in range(1, len(inds)):
        for i in range(inds[r-1], inds[r]):
            m[i][s] = inds[r] - i

ans = 0
i = ls - 1
for t in T:
    cnt = m[i][t]
    if cnt == -1:
        print(-1)
        exit()
    ans += cnt
    i = (i + cnt) % ls
print(ans)