C++

#include<iostream>
using namespace std;

int main() {
    float a, b, c, d;
    cin >> a >> b >> c >> d;
    if (a == b and b == c and c == d){
        cout << "YES";
    } 
    else {
        cout << "NO";
    }
}

Python

a, b, c, d = map(float, input().split())

if a == b == c == d:
    print("YES")
else:
    print("NO")