#include <iostream>
#include <bitset>
#include <iomanip>
#include <string>
#include <vector>
#include <cmath>
#include <queue>
#include <algorithm>

using namespace std;

#define ll long long
#define vecll vector<long long>
#define vec2ll vector<vector<long long>>
#define vecbool vector<bool>
#define vecpairll vector<pair<long long,long long>>
#define forll(s,a,b) for(long long s = a;s < b;s++)
#define forllde(s,a) for(long long s = a;s > 0;s--)

int main()
{
	ll a,b;
	string s = "unsafe";

	cin >> a >> b;

	if (a > b)
		s = "safe";

	cout << s;

}
