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>
using namespace std;
#define rep(i, n) for(int i = 0; i < (int)n; i++)
#define debug(x)      cerr << "L" << __LINE__ << ": " << #x << " = " << (x) << endl
#define debugvec(v)   rep(i, v.size()) cerr << "L" << __LINE__ << ": " << #v << "[" << i << "] = " << v[i] << endl;
#define debugvec2(v)  cerr << "L" << __LINE__ << ": " << #v << " = { "; rep(i, v.size()) cerr << v[i] << (i + 1 == v.size() ? "" : ", "); cerr << " }" << endl;
typedef long long ll;  /* 10^18 くらいまでいける */

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

  return 0;
}