#include<bits/stdc++.h>
using namespace std;
int main()
{
 ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);
 unsigned int a,b;
 cin>>a>>b;
 if(a>=1&&a<=100&&b>=1&&b<=100)
 {
  if(a<=b)
 cout<<"unsafe"<<"\n";
 else
 cout<<"safe"<<"\n";
 }
 
 
 
 
 return 0;
}