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: Accepted)

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cmath>
using namespace std;
using ll=long long;
#define rep(i,a,b) for(ll i=a;i<ll(b);i++)
#define repr(i,a,b) for(ll i=a;i>=ll(b);i--)
#define endl "\n"
#define ALL(x) x.begin(),x.end()
#define ALLR(x) x.rbegin(),x.rend()
#define INF 1e9
#define DEBUG(x) cout<<"debug: "<<x<<endl

int s, w;
int main() {
    cin >> s >> w;
    if(w >= s) cout << "unsafe" << endl;
    else cout << "safe" << endl;
    return 0;
}