#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define ff first
#define ss second

void io(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    #ifdef LOCAL
        freopen("input.txt","r",stdin);
        freopen("output.txt","w",stdout);
    #endif
}
auto seed = chrono::high_resolution_clock::now().time_since_epoch().count();
mt19937_64 mt(seed);
#ifdef LOCAL
    #include "debug.h"
#else
    #define debug(...) 42
#endif

const int N = 2e3 + 50;
const int mod = 998244353 ;

int main(){
    io();

    int s, w;
    cin >> s >> w;
    if(s > w)
        cout << "safe";
    else
        cout << "unsafe";    

}

