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 */
#include "bits/stdc++.h"
/* namespace */
using namespace std;

/* typedef */
/* long系 */
typedef long long ll;   // long long
typedef long double ld; // long double
/* vector系 */
typedef vector<int> vi;                    // intのvector
typedef vector<double> vd;                 // doubleのvector
typedef vector<ll> vll;                    // llのvector
typedef vector<ld> vld;                    // ldのvector
typedef vector<pair<int, int>> vi_i;       // i_iのvector
typedef vector<pair<double, double>> vd_d; // d_dのvector
typedef vector<pair<ll, ll>> vl_l;         // l_lのvector
typedef vector<pair<ld, ld>> vld_ld;       // ld_ldのvector
typedef vector<string> vs;                 // stringのvector
/* pair系 */
typedef pair<int, int> i_i;       // int同士のpair
typedef pair<double, double> d_d; // double同士のpair
typedef pair<ll, ll> l_l;         // ll同士のpair
typedef pair<ld, ld> ld_ld;       // ld同士のpair

/* define */
#define pb push_back              // push_back
#define all(v) v.begin(), v.end() // コンテナ全体
#define PI (acos(-1))             // 円周率pi

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

int main(int argc, char *argv[])
{
    // cin, coutの高速化、ただしcのIOと一緒にしない
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    // fixed -> 少数の形で出力、setprecision -> 少数第n位まで出力
    cout << fixed << setprecision(15);
    // main実行
    Main();

    return 0;
}