 //om namah shivaaay//
#include <bits/stdc++.h>
#define Om_namah_Shivaay ios::sync_with_stdio(false),cin.tie(NULL),cout.tie(NULL)
 #define ll long long
 using namespace std;
 int main()
 {
    Om_namah_Shivaay;
    int s,w;
    cin>>s>>w;
    if(s<=w) cout<<"unsafe";
    if(s>w) cout<<"safe";
}
