#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize ("Ofast")
#pragma GCC optimize("unroll-loops,no-stack-protector")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
 
using namespace __gnu_pbds;
using namespace std;

#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define fbo find_by_order
#define ook order_of_key
 
template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
 
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<long long,long long> ii; 	
typedef complex<long double> com;

const ll mod = 1e9+7;

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
    ll n,s;
    cin >> n >> s;
    if (n <= s){
        cout << "unsafe" << endl;
    } else {
        cout << "safe" << endl;
    }
}