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: Accepted)

#include <bits/stdc++.h>

#pragma region Macro
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define FOR(i, m, n) for(int i = m;i < n;i++)
#define SORT(v) sort(v.begin(), v.end())
#define pb(a) push_back(a)
#define eb(a) emplace_back(a)
#define vi vector<int>
#define vvi vector<vector<int>>
#define chmax(x,y) (x = max(x,y))
#define chmin(x,y) (x = min(x,y))

using namespace std;
typedef long long ll;
typedef pair<int, int> P;
#pragma endregion

void solve(){
	#define int ll
	// ここに処理を記述
	// コンパイル時はエイリアス「gpp」--> c++17でコンパイル
	int S, W;
	cin >> S >> W;

	if(W >= S){
		cout << "unsafe" << endl;
	}
	else{
		cout << "safe" << endl;
	}
}

signed main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout << fixed << setprecision(15);

	solve();
	return 0;
}