#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#define x first
#define y second
#define pb push_back
#define mp make_pair
#define all(v) v.begin(),v.end()
#define sz(v) (int)v.size()
#define up_b upper_bound
#define low_b lower_bound
#define nl '\n'

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef long double ld;

typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update>ordered_set;

const int N=2e5+11;
const int M=3e6+11;
const int W=1e3+11;
const int inf=1e9;
const ll INF=1e18;
const ll mod=1e9+7;
const ld EPS=1e-9;

int main(){
  ios_base::sync_with_stdio(0);
  cin.tie(0),cout.tie(0);
  int a,b;
  cin>>a>>b;
  if(a>b)cout<<"safe";
  else cout<<"unsafe";
}
