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 <stdio.h>
#include <iostream>
#include <cstdlib>
#include <iomanip>
#include <cmath>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdlib>
#include <limits>
#include <numeric>
#include <queue>
#include <set>
#include <bitset>
#include <map>

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<string> vs;
typedef vector<char> vc;
typedef vector<long long> vll;
typedef queue<int, int> qii;
typedef pair<int, int> pii;
typedef pair<string, int> psi;

#define PI 3.14159265359
#define rep(i,a) for(int i=0;i<a;i++)

//int型を受け取ってその桁数を返す
int check_digits(int n, int m) {
	int digits = 0;
	while (n != 0) {
		n /= m;
		digits++;
	}
	return digits;
}

//int型を受け取ってその各桁の和を返す
int sum_digits(int n) {
	int sum = 0;
	int N = n;
	while (N) {
		sum += N % 10;
		N /= 10;
	}
	return sum;
}


//最大公約数を返す関数
int gcd(int n, int m) {
	while (n != 0) {
		if (n < m) swap(n, m);
		n = n % m;
	}
	return m;
}


//2点間の距離を返す
float dis(int x1, int y1, int x2, int y2) {
	return sqrt(pow(abs(x1 - x2), 2) + pow(abs(y1 - y2), 2));
}


//入力された文字列が回文か判断してboolを返す
bool is_kaibun(string s) {
	string s_r(s.rbegin(), s.rend());
	return (s == s_r);
}


void yes() { cout << "Yes" << endl; }
void no() { cout << "No" << endl; }


//提出言語もしっかり確認して…
//問題文を落ち着いて読む！
//型に注意！！
//出力例もちゃんと全部見る！！！！！
int main() {
	int s, w;
	cin >> s >> w;
	if (w >= s) {
		cout << "unsafe" << endl;
	}
	else {
		cout << "safe" << endl;
	}

	system("pause");
	return 0;
}