#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;

#define print(a) {for(auto xxxxx : (a)) cout << xxxxx << ' '; cout << '\n';}
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define fi first
#define se second
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()

ll next(){ll x; cin >> x; return x;}
const int maxn = 1e5 + 3, intf = 2e9;
const ll inf = 2e18, mod = 998244353;
const ld eps = 1e-6;


void solve(){
	int a , b; cin >> a >> b;
	if (a <= b){
		cout << "unsafe\n";
	} else {
		cout << "safe\n";
	}
}


signed main(){
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0); cout.precision(20);
    
    for (int t = 1; t--;) {
    	solve();
    }

	return 0;
}
/*


*/

