#include<algorithm>
#include<iostream>
#include<stdio.h>
#include<iostream>
#include<stdio.h>
#include<vector>
#include<set>
#include<string>
#include<iomanip>
#include<queue>
#include<functional>
#include<cmath>
#include<map>
#define rep(i,n) for(int i=0; i<(int)n; i++)//n回繰り返す
#define rrep(i,n)for(int i=n-1;i>=0;i--)
using namespace std;
using ll = long long;
using P = pair<int, int>;
using graph = vector<vector<int>>;
const ll mod = pow(10, 9) + 7;
const int INF = 1e9;
const ll LINF = 1e18;
template<class T> inline bool chmax(T & a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T & a, T b) { if (a > b) { a = b; return 1; } return 0; }

int main() {
    int S, V; cin >> S >> V;
    if (S <= V) {
        cout << "unsafe" << endl;
    }
    else {
        cout << "safe" << endl;
    }
    



}

   

    
    



    
                

 











































































































































