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 Ruby (2.3.3) (judge verdict: Time Limit Exceeded)

require 'pp'
# 10 -1 33
s = gets.chomp.chars
t = gets.chomp.chars

arr_2d = []
t.size.times do |ti|
  arr_1d = []
  s.size.times do |si|
    arr_1d[si] = s[si] == t[ti]
  end
  arr_2d << arr_1d
end
# pp arr_2d

count = 0

pre_si = s.size + 10
t.size.times do |ti|
  s.size.times do |si|
    if arr_2d[ti][si]
      if pre_si >= si # 自分のほうが前のより小さいOR等しいなら
        count += s.size
      end
      pre_si = si
      break # s loop
    end
    if si == s.size-1
      p(-1)
      exit
    end
  end
end
# p count
count -= s.size
count += pre_si+1
p count