11

#include <iostream>
#include <string>

using namespace std;

int KMP(string s, string p) {
    int ans = -1;
    int n = s.size();
    int m = p.size();

    int *d = new int[m];
    d[0] = 0;
    int j = 0;
    int i = 1;
    while (i < m) {
        while (j > 0 && p[j] != p[i])
            j = d[j - 1];
        if (p[j] == p[i])
            j++;
        d[i] = j;
        i++;
    }
    j = 0;
    i = 0;
    while (i < n) {
        while (j > 0 && p[j] != s[i])
            j = d[j - 1];
        if (p[j] == s[i])
            j++;
        if (j == m) {
            ans = i - j + 1;
            break;
        }
        i ++;
    }
    delete [] d;
    return ans;
}

int main() {
    string s, p;
    cin >> s >> p;
    cout << KMP(s, p) << endl;
    return 0;
}