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++ (Clang 10.0.0) (judge verdict: Wrong Answer)

#include <cstdio>
#include <cmath>
#include <vector>

#define REP(i, n) for (int i = 0; i < n; ++i)
#define FOR(i, x, n) for (int i = x; i < n; ++i)

typedef std::vector<int> v;
typedef std::vector<std::vector<int>> vv;
typedef unsigned long long ull;

int main(void)
{
    int s, w;
    scanf("%d %d", s, w);
    if (s <= w)
    {
        puts("unsafe");
    }
    else
    {
        puts("safe");
    }
}