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)

#################### library ####################


#################### naive ####################


#################### process ####################

function read_input()
	s = chomp(readline())
	t = chomp(readline())
	return (s, t)
end

function make_next_pos(v, L)
	w = zeros(Int, L)
	p = 1
	for q in v
		for k in p:q-1
			w[k] = q
		end
		p = q
	end
	q = v[1]
	for k in p:L
		w[k] = q
	end
	return w
end

function f()
	s, t = read_input()
	for c in t
		if search(s, c) == 0
			return -1
		end
	end
	
	L = length(s)
	dic::Dict{Char,Array{Int}} = Dict()
	for k in 1:length(s)
		if haskey(dic, s[k])
			push!(dic[s[k]], k)
		else
			dic[s[k]] = [k]
		end
	end
	
	table::Dict{Char,Array{Int}} = Dict()
	for (c, v) in dic
		table[c] = make_next_pos(v, L)
	end
	
	p = L
	i = -1
	for c in t
		q = table[c][p]
		i += (q-p-1+L)%L+1
		p = q
	end
	return i+1
end


#################### main ####################

println(f())