#include<bits/stdc++.h>
using namespace std;
string a,b;
int main()
{
    cin>>a>>b;
    if(a.find(b)!=a.npos)    //如果b是a的子串 
    {
        cout<<b<<" is substring of "<<a<<endl;
    }
    else if(b.find(a)!=b.npos)   //如果a是b的子串 
    {
        cout<<a<<" is substring of "<<b<<endl;
    }
    else      //如果没有子串关系 
    {
        cout<<"No substring"<<endl;
    }
    return 0;
}

#include<bits/stdc++.h> using namespace std; string a,b; int main() { cin>>a>>b; if(a.find(b)!=a.npos) //如果b是a的子串 { cout<<b<<" is substring of "<<a<<endl; } else if(b.find(a)!=b.npos) //如果a是b的子串 { cout<<a<<" is substring of "<<b<<endl; } else //如果没有子串关系 { cout<<"No substring"<<endl; } return 0; }