Problem:
Score : 100 points

Problem Statement

There are S sheep and W wolves.

If the number of wolves is greater than or equal to that of sheep, the wolves will attack the sheep.

If the wolves will attack the sheep, print unsafe; otherwise, print safe.

Constraints

1 \leq S \leq 100

1 \leq W \leq 100

Input

Input is given from Standard Input in the following format:

S W

Output

If the wolves will attack the sheep, print unsafe; otherwise, print safe.

Sample Input 1

4 5

Sample Output 1

unsafe

There are four sheep and five wolves. The number of wolves is not less than that of sheep, so they will attack them.

Sample Input 2

100 2

Sample Output 2

safe

Many a sheep drive away two wolves.

Sample Input 3

10 10

Sample Output 3

unsafe

Solution in C++ (GCC 9.2.1) (judge verdict: Wrong Answer)

#include <iostream>
#include <iomanip>
#include <string>
#include <string.h>
#include <math.h>
#include <cmath>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <algorithm>
#include <utility>
#include <deque>
#include <queue>
#include <functional>

#define rep(i, n) for(int i = 0; i < n; ++i)
#define REP(i, m, n) for(int i = m; i < n; ++i)
#define rrep(i,n) for(int i = n; i >= 0; --i)
#define RREP(i, m, n) for(int i = n; i >= m; --i)
#define llrep(i, n) for(ll i = 0; i < n; ++i)
#define llREP(i, m, n) for(ll i = m; i < n; ++i)
#define llrrep(i,n) for(ll i = n; i >= 0; --i)
#define llRREP(i, m, n) for(ll i = n; i >= m; --i)

using ll = long long;
using ull = unsigned long long;
using pii = std::pair<int, int>;
using pll = std::pair<long long, long long>;

using namespace std;

const long long _MOD = 1000000007;
const long long MOD = 998244353;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int s, w;
	cin >> s >> w;

	if (s & 1)++s;

	if (s / 2 <= w) {
		cout << "unsafe" << "\n";
	}
	else {
		cout << "safe" << "\n";
	}

	return 0;
}