#include <bits/stdc++.h>

using namespace std;

int main() {
    string s1, s2;
    getline(cin, s1);
    getline(cin, s2);
    //查找子串位置
    if (s2.find(s1) != s2.npos) {
        cout << s1 << " is substring of " << s2 << endl;
    } else {
        cout << "No substring" << endl;
    }
    return 0;
}