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: Time Limit Exceeded)

'''p=input().rstrip().split(' ')
l=[]
q=[]
for i in range(0,int(p[0])-1):
    u=input().rstrip().split(' ')
    D=[]
    D.append(int(u[0]))
    E=[]
    E.append(int(u[1]))
    if D not in l:
        l.append(D)
        q.append(E)
    else:
        V=l.index(D)
        q[V].append(int(u[1]))
w=[0]*int(p[0])
S=[]
D=[]
for i in range(0,int(p[1])):
    u=input().rstrip().split(' ')
    if int(u[0]) not in S:
        S.append(int(u[0]))
        D.append(int(u[1]))
    else:
        G=S.index(int(u[0]))
        D[G]+=int(u[1])
V=[]
W=[]
for i in range(1,int(p[0])+1):
    DD=[]
    DD.append(i)
    XX=[]
    if DD in l:
        V.append(i)
        C=l.index(DD)
        A=q[C];
        G=0;
        while(len(A)!=0):
            X=A[0]
            XX.append(X)
            O=[]
            O.append(X)
            if O in l:
                Z=l.index(O)
                B=q[Z];
                for j in range(0,len(B)):
                    A.append(B[j])
            del(A[0])
    XX=list(set(XX))
    W.append(XX)
#print(V,W)
#print(S,D)
for i in range(0,len(S)):
    if S[i] in V:
        H=V.index(S[i])
        J=W[H];
        w[S[i]-1]+=D[i]
        for j in range(0,len(J)):
            w[J[j]-1]+=D[i];
    else:
        w[S[i]-1]+=D[i]
print(*w)'''


'''s=input().rstrip()
x=list(s)
t=input().rstrip()
y=list(t)
VVV=0;
if(1):
    C=-1;
    D=0;
    for i in range(0,len(y)):
        if y[i] not in x:
            VVV=1;
            break;
        T=y[i]
        CC=x[C+1:len(x)]
        if T in CC:
            V=CC.index(T)
            C=V+(C+1);
        else:
            D+=1;
            V=x.index(T)
            C=V;
    if VVV==1:
        print(-1)
    else:
        print(D*len(x) + C+1)'''


s=input().rstrip()
x=list(s)
t=input().rstrip()
y=list(t)
l=[]
q=[]
w=[]
S=[]
D=[]
d=0;
for i in range(0,26):
    D=[]
    D.append(-1)
    l.append(D)
for i in range(0,len(s)):
    A=ord(s[i])-97;
    l[A].append(i)
for i in range(0,26):
    del(l[i][0])
KK=0;
for i in range(0,len(y)):
    if y[i] not in x:
        KK=1;
        break;        
    if i==0:
        A=ord(y[i])-97;
        C=l[A][0];
    else:
        A=ord(y[i])-97;
        R=l[A];
        I=0;
        J=len(R)-1;
        H=-999;
        while(I<=J):
            m=(I+J)//2;
            if R[m]<=C:
                I=m+1;
            else:
                H=R[m];
                J=m-1;
        if H==-999:
            C=R[0];
            d+=1;
        else:
            C=H;
if KK==1:
    print(-1)
else:
    print(d*len(x)+1+C)