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<bits/stdc++.h>
typedef long long ll;
typedef long double ld;
using namespace std;

using Pii = pair<int, int>;
using Pll = pair<ll, ll>;

#define REP(i, l, n) for(int i=(l), i##_len=(n); i<i##_len; ++i)
#define ALL(x) (x).begin(),(x).end()
#define pb push_back

ll gcd(ll a,ll b){return b ? gcd(b,a%b) : a;}
ll lcm(ll a,ll b){return a/gcd(a,b)*b;}

char alpha[26] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};

int dx[4] = {-1, 1, 0, 0};
int dy[4] = {0, 0, 1, -1};

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