#include<bits/stdc++.h>
using namespace std;
#define FIO ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define mod 1000000007
#define test ll tx; tx=1; while(tx--)
typedef long long int ll;
int main() {
    FIO;
    test{
        ll n,m;
        cin>>n>>m;
        n>m ? cout<<"safe\n" : cout<<"unsafe\n";
    }
	return 0;
}
