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 PyPy2 (5.6.0) (judge verdict: Time Limit Exceeded)

import sys
input = sys.stdin.readline
s = input().rstrip("\n")
t = input().rstrip("\n")
dic = {"a":[],"b":[],"c":[],"d":[],"e":[],"f":[],"g":[],"h":[],"i":[],"j":[],"k":[],"l":[],"m":[],"n":[],"o":[],"p":[],"q":[],"r":[],"s":[],"t":[],"u":[],"v":[],"w":[],"x":[],"y":[],"z":[]}
for i,c in enumerate(s):
    dic[c] += [i]
#print(dic)
cnt = 0
ind = -1
ans = 0
for c in t:
    d = dic[c]
#    print("c=",c,"d=",d)
    for i in d: #iは各文字のindex 昇順
#        print("i=",i)
        if ind < i: #もし現在位置<iなら
            ind = i
#            print("found, ind=",i)
            break
    else:
#        print("not found")
        cnt += 1
        if d:
            ind = d[0]
        else:
#            print("!!!!!!!!!!!!!")
            ans = -1
            break
print(cnt*len(s)+ind+1 if ans > -1 else -1)