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 <bits/stdc++.h>
using namespace std;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main() {
    int S, W;
    cin >> S >> W;
    if (S/2 <= W) {
        cout << "unsafe" << endl;
    } else {
        cout << "safe" << endl;
    }
}