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;
typedef long long int ll;
typedef pair<ll, ll> P;
#define MD 1000000007
#define INF 1ll<<60
const double PI=3.141592653589;
template <typename T>
std::string tostr(const T &t){std::ostringstream os;os << t;return os.str();}
int dx[4]={1, 0, -1, 0}, dy[4]={0, 1, 0, -1};

int main(){
    int s,w;
    cin>>s>>w;
    if(w>=((s+2-1)/2)) cout<<"unsafe"<<endl;
    else cout<<"safe"<<endl;
    return 0;
}