S = input()
T = input()
count = 0

while True:

    if T in S:
        if len(T) == 1:
            print(-1)
            exit()

        replaceChar = T[:-1] + "." + T[-1]
        S = S.replace(T, replaceChar, 1)
        count += 1
    else:
        break
print(count)