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: Wrong Answer)

s = gets.chomp
t = gets.chomp


lidx = 0
found = true
lgt = 0
strCnt = 0
# 一周して文字が見つからなかったら終了
t.chars do |c|
  idx = s.index(c, lidx)
  if idx
    if idx == 0
      lgt += 1
    end
    lgt += idx
    lidx = idx
  else
    strCnt += 1 # 文字列数の累計
    idx = s.index(c, 0) # 次はまた0から走査
    lgt = strCnt * s.length # 見つからなかったら文字列数分の長さを入れる
    if idx
      if idx == 0
        lgt += 1
      end
      lgt += idx
      lidx = idx
    else
      found = false
      break
    end
  end
end

if found
  puts lgt
else
  puts (-1)
end