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)

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstdio>
#include <vector>
#include <utility>
#include <algorithm>
#include <string>
#include <queue>
#include <stack>
#include <tuple>
#include <list>
#include <set>
#include <map>
#include <functional>
#include <cmath>
#include <cstring>
#include <cstdlib>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;

#define xx first
#define yy second
#define $1 first
#define $2 second

typedef struct _schedule {
	int s, t;
	int idx;
	char c;
} schedule;

bool operator < (const schedule& a, const schedule& b) {
	return a.t < b.t;
}

bool cmp(schedule& a, schedule& b) {
	return a.idx < b.idx;
}

void solveCase() {
	ios::sync_with_stdio(false);
	cin.tie(NULL); cout.tie(NULL);
	ll s, w; cin >> s >> w;
	if (s >= w) cout << "safe";
	else cout << "unsafe";

}

int main() {

#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
#endif
	solveCase();
}