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 Julia (0.5.0) (judge verdict: Accepted)

s=chomp(readline())
t=chomp(readline())
N=length(s)
nxt=zeros(Int,N,26)
nownxt=-ones(Int,26)
for i=2*N:-1:1
	if i<=N
		for j=1:26
			nxt[i,j]=nownxt[j]
		end
	end
	nownxt[Int(s[mod1(i,N)])-96]=i-1
end
p=-1
ans=0
for c=t
	q=0
	if p<0
		q=nownxt[Int(c)-96]
	else
		q=nxt[p+1,Int(c)-96]
	end
	if q<0
		println(-1)
		exit()
	end
	ans+=q-p
	p=q%N
end
println(ans)