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: Wrong Answer)

import sys,collections as cl,bisect as bs
sys.setrecursionlimit(100000)
mod = 10**9+7
Max = sys.maxsize
def l(): #intのlist
    return list(map(int,input().split()))
def m(): #複数文字
    return map(int,input().split())
def onem(): #Nとかの取得
    return int(input())
def s(x): #圧縮
    a = []
    aa = x[0]
    su = 1
    for i in range(len(x)-1):
        if aa != x[i+1]:
            a.append([aa,su])
            aa = x[i+1]
            su = 1
        else:
            su += 1
    a.append([aa,su])
    return a
def jo(x): #listをスペースごとに分ける
    return " ".join(map(str,x))
def max2(x): #他のときもどうように作成可能
    return max(map(max,x))
import fractions
from functools import reduce
def gcd(*numbers):
    return reduce(fractions.gcd, numbers)

def gcd_list(numbers):
    return reduce(fractions.gcd, numbers)
def lcm_base(x, y):
    return (x * y) // fractions.gcd(x, y)

def lcm(*numbers):
    return reduce(lcm_base, numbers, 1)

def lcm_list(numbers):
    return reduce(lcm_base, numbers, 1)


s = list(input())

t = list(input())
flag = -1
on = [[-1 for j in range(len(s))] for i in range(26)]

al = [-1 for i in range(26)]
alll = [0 for i in range(26)]
for i in range(len(s)):
    k = ord(s[i]) - 97
    on[k][i] = i
    if al[k] == -1:
        al[k] = i

for i in range(26):
    for j in range(len(s)-2,-1,-1):
        if on[i][j+1] != -1 and on[i][j] == -1:
            on[i][j] = on[i][j+1]

co = 0
su = 0
ppp = 0
t = cl.deque(t)
while t:
    k = t.popleft()
    kkk = al[ord(k)-97]
    ppp = kkk+1
    if kkk == -1:
        print(kkk)
        exit()
    while True:
        if len(t) == 0:
            break
        k = t.popleft()
        kk = on[ord(k)-97][kkk]
        if kkk >= kk:
            break
        else:
            ppp = kk+1
            kkk = kk
    if len(t) != 0:
        co += 1

print(len(s)*co + ppp)