#include <iostream>
using namespace std;
int main()
{
int A[5];
int summa=0;
for(int i = 0;i<5;i++)
{
    cin>>A[i];
    summa+=A[i];
}
if((summa/1000)>=1)
    cout <<"chetirehznachnoe"<<endl;
else
    cout << "net"<<endl;
return 0;
}