/*
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("unroll-loops")
*/
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>

using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;

#define IOS ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define pb push_back
#define rev reverse
#define all(x) x.begin(), x.end()
#define ub upper_bound
#define lb lower_bound
#define ll long long
#define endl '\n'
#define ull unsigned long long
#define sz(x) (int)x.size()

template<typename T> using ordered_set = tree <T, null_type, less <T>, rb_tree_tag, tree_order_statistics_node_update>;

const ll inf = 1e9+7;
const ll N = 1e5+1;
const ll mod = 1e9+7;
const ll P = 31;

int main() {
    IOS
    ll a, b;
    cin >> a >> b;
    if(b >= a) {
        cout << "unsafe" << endl;
    }
    else {
        cout << "safe" << endl;
    }
    return 0;
}
