#include<bits/stdc++.h>

using namespace std;

typedef long long int ll;

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

int main()
{
	int t = 1;
	//cin >> t;
	while(t--)
	{
		solve();
	}
	return 0;
}

