#include<iostream>
#include<string>
using namespace std;
	int main(){
	int x;
    int a[21];
	string m,n;
	getline(cin,m);
	getline(cin,n);
	x=n.find(m);
	if(x!=-1)
	{
		cout<<m<<" is substring of "<<n;
		return 0;
	}
	else{
	cout<<"No substring";
	return 0;
	}	
	x=0;
	x=m.find(n);
	if(x==-1)
	{
		cout<<n<<" is substring of "<<m;
		return 0;
	}
	else{
	cout<<"No substring";
	return 0;
	}	
  return 0;
}