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 <iostream>
#include <iomanip>
#include <cstdio>
#include <string>
#include <queue>
#include <deque>
#include <list>
#include <vector>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <complex>
#include <cmath>
#include <limits>
#include <cfloat>
#include <climits>
#include <ctime>
#include <cassert>
#include <numeric>
#include <fstream>
#include <functional>
#include <bitset>

using namespace std;


#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define repr(i,n) for(int (i)=(n); (i)>=(0); (i)--)
#define SIZE(x) ((int)(x).size())
#define GCD(a, b) int gcd(int a,int b){return b?gcd(b,a%b):a;}
#define QP(a, b) int qp(int a,ll b){int ans=1;do{if(b&1)ans=1ll*ans*a%mo;a=1ll*a*a%mo;}while(b>>=1);return ans;}
#define pb(a) push_back(a)
#define mp(a,b) make_pair(a,b)
#define all(v) (v).begin(),(v).end()


template<typename T> void chmax(T &a, T b) {a = max(a, b);}
template<typename T> void chmin(T &a, T b) {a = min(a, b);}
template<typename T> void chadd(T &a, T b) {a = a + b;}
template<typename A, size_t N, typename T>
void FILL(A (&array)[N], const T &val){
    std::fill( (T*)array, (T*)(array+N), val );
}

typedef vector<int, int> vint;
typedef pair<int,int> pint;
typedef vector<pint>vpint;
typedef long long ll;

int dx[] = {0, 0, 1, -1};
int dy[] = {1, -1, 0, 0};
const ll INF = 1LL << 60;
const ll MOD = 1000000007LL;


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