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: Runtime Error)

from bisect import bisect_right

s = input()
t = input()

char_list = [[] for i in range(26)]

for i in range(2*len(s)):
        if i<len(s):
                char_list[ord(s[i])-97].append(i)
        else:
                char_list[ord(s[i-len(s)])-97].append(i)

INF = 10**27

for i in range(26):
        char_list[i].append(INF)

next_list = [[char_list[j][bisect_right(char_list[j],i)] for j in range(26)] for i in range(len(s))]

flag = False
for i in range(len(s)):
        if t[0]==s[i]:
                flag=True
                x = i
                y = i
                break
if flag:
        flag2 = True
        for i ina range(1,len(t)):
                n = next_list[x][ord(t[i])-97]
                y += n - x
                x = n%(len(s))
                if y >= INF:
                        flag2=False
                        break
        if flag2:
                print(y+1)
        else:
                print(-1)
else:
        print(-1)