
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")


#include<bits/stdc++.h>

using namespace std;
#define ll long long
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define lb lower_bound
#define ub upper_bound
#define ins insert
#define ull unsigned long long
#define repi(i,a) for(auto i = a.begin(); i!= a.end() ;++i) 
#define repdi(i,a) for(auto i = a.rbegin(); i!=a.rend();++i) 
#define rep(i, begin, end) for (__typeof(end) i = (begin) - ((begin) > (end)); i != (end) - ((begin) > (end)); i += 1 - 2 * ((begin) > (end)))
#define MOD 1000000007
#define ff first
#define ss second
#define fast ios::sync_with_stdio(0) , cin.tie(0) , cout.tie(0); 
#define nl "\n"
#define INF 1e18
#define sz(a) (int)a.size() 
#define all(a) a.begin(),a.end()
#define M 998244353
#define limit 100000000

typedef vector<ll> vll;
typedef pair<ll,ll> pii;
typedef vector<pii> vpi;
typedef vector<vector<ll> > vv;

#define error(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator<string> _it(_ss); err(_it, args); }

void err(istream_iterator<string> it) {}
template<typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
	cerr << *it << " = " << a << endl;
	err(++it, args...);
}

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

signed main() {

    fast;
	int t=1;
	rep(i,0,t) {
		solve() ;
	}
	return 0;
}