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 Python (3.4.3) (judge verdict: Runtime Error)

def ssearch(c, p):
  
  if p >= len(s):
    p = p % len(s)
  
  key = c + str(p)

  if(key in dic):
    pass
  elif s2[p] == c:
    dic[key] = 1
  else:
    dic[key] = ssearch(c, p+1) + 1

#  print('DEBUG '+key+' '+str(dic[key]))
    
  return dic[key]

s  = input()
s2 = s + s
t  = input()

ptr = 0
cnt = 0
dic = {}
for i in range(len(t)):
  if t[i] in s:
    cnt += ssearch(t[i], ptr)
    ptr  = cnt % len(s)
#    print('DEBUG2 '+ str(len(s)) + ' ' + str(ptr))
  else:
    cnt = -1
    break
  
print(cnt)