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: Time Limit Exceeded)

s = input()
t = input()

alphabet = 'abcdefghijklmnopqrstuvwxyz'
alphaset = set(s)
cache = []

def search(origin, c, offset):
    if c not in alphaset:
        return None
    offset = offset % len(origin)
    o = origin[offset:] + origin
    try:
        return o.index(c)
    except ValueError:
        return None


cache.append({c2: 0 for c2 in alphabet})
for c2 in alphabet:
    offset2 = search(s, c2, 1)
    if offset2 is None:
        cache[0][c2] = None
        continue
    cache[0][c2] = offset2 + 1
for i in range(1, len(s)):
    cache.append({c2: 0 for c2 in alphabet})
    for c2 in alphabet:
        if s[i] == c2:
            offset2 = search(s, c2, i + 1)
            if offset2 is None:
                cache[i][c2] = None
                continue
            cache[i][c2] = offset2 + 1
        else:
            offset2 = cache[i-1][c2]
            if offset2 is None:
                cache[i][c2] = None
                continue
            cache[i][c2] = offset2 - 1


a = search(s, t[0], 0)
if a is None:
    print(-1)
    exit()

result = a
for i in range(1, len(t)):
    k = cache[result % len(s)][t[i]]
    if k is None:
        print(-1)
        exit()
    result += k

print(result+1)