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)

#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>

using namespace std;

//vector string deque break continue
#define forn(i, s, f) for (int i = (int)s; i < (int)f; i++)
#define ll long long
#define ull unsigned long long
#define ld long double
#define pii pair <int, int>
#define fs first
#define sc second
#define pf push_front
#define pb push_back
#define pop_f pop_front
#define pop_b pop_back
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) (int)(x).size()

template <typename T> istream& operator>>(istream& in, vector <T>& a) {for (auto& i : a) in >> i; return in;}
template <typename T> ostream& operator<<(ostream& out, vector <T>& a)  {for (auto& i : a) out << i << " "; return out;}
template <typename T, typename U> void chkmin(T& a, U b) {if (a > b) a = b;}
template <typename T, typename U> void chkmax(T& a, U b) {if (a < b) a = b;}

int main() {
    ios_base::sync_with_stdio(0), cin.tie(0);
    int s, w;
    cin >> s >> w;
    if (w >= s)
        cout << "unsafe";
    else
        cout << "safe";
    return 0;
}