#include <bits/stdc++.h>
// #include "atcoder/modint"

using i64 = long long;
// using Fp = atcoder::modint998244353;

int main() {
    std::string S, T;
    std::cin >> S >> T;
    const int N = (int)S.size();
    if (T.size() == 1) {
        const auto s = std::count(S.begin(), S.end(), T[0]);
        if (s) std::cout << -1 << std::endl;
        else std::cout << 0 << std::endl;
        return 0;
    }
    std::vector<std::pair<char, int>> P;
    {
        int last = 0;
        for (int i = 0; i < N; ++i) {
            if (S[i] != S[last]) {
                P.push_back({S[last], i - last});
                last = i;
            }
        }
        P.push_back({S[last], N - last});
    }
    const int U = (int)P.size();
    if (T.size() == 2 and T[0] != T[1]) {
        i64 ans = 0;
        for (int i = 0; i < U; ++i) {
            if (i != 0 and P[i].first == T[1]) ++ans;
        }
        std::cout << ans << std::endl;
    } else if (T.size() == 2) {

    }
}