#include <bits/stdc++.h>
using namespace std;
using ll = long long;
typedef vector<int> vec1;
typedef vector<string> vec2;
typedef vector<double> vec3;

int main() {
  
  int a, b;
  cin >> a >> b;

  if(b >= s) {
    cout << "unsafe" << endl;
  } else {
    cout << "safe" << endl;
  }
}