#include <bits/stdc++.h>

//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
//#pragma GCC optimize("Ofast")
//1.0 * clock() / CLOCKS_PER_SEC

#define fi first
#define se second
#define ll long long
#define dl double long

using namespace std;

const int NN = 1e3 + 7;
const int N = 2e5 + 7;
const int M = 22;
const ll mod = 1e9 + 7;
const ll inf = 1e18 + 7;
const dl rf = 1e-14;
const int B = sqrt(N);



void solve1()
{
    int s,w;
    cin >> s >> w;
    if( s <= w )cout << "unsafe";
    else cout << "safe";
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    //freopen( "input.txt" , "r" , stdin );
    //freopen( "output.txt" , "w" , stdout );

    int cghf = 1;//cin >> cghf;
    while( cghf-- ){
        solve1();
    }
}
