#include <bits/stdc++.h>
using namespace std;
int main(){
	string s,s1;
	cin >> s;
	cin >> s1; 
	int len =s.length(),len1=s1.length(),flag;
	for (int i = 0;i<len1;i++)
	{
		flag = 1;
		for (int j = 0;j<len;j++)
		{
			if (s1[i+j] != s[j])
			{
				flag = 0;
				break;
			}
		}
		if (flag)
		{
			cout << s << " is substring of "<< s1;
			return 0;
		}
	}
		cout << "No substring";
   return 0;
}