#include <stdio.h>
#include <clocale>
#include <bits/stdc++.h>

#pragma GCC optimize("Ofast")
#pragma GCC optimize("O3")

using namespace std;

#define ll long long

const int inf = (int)2e9;
const int mod = (int)1e9 + 7;
const double error = 1e-5;

struct point {

    int x, y;

    point() {
        x = inf;
        y = inf;
    }

    point(int _x, int _y) {
        x = _x;
        y = _y;
    }

    bool operator < (point &other) const {

        if(x != other.x) {
            return x < other.x;
        }

        return y < other.y;
    }
};

int sqr(int a) {
    return a * a;
}

int dist(point a, point b) {
    return sqr(a.x - b.x) + sqr(a.y - b.y);
}

int main() {
    freopen("quadr.in", "r", stdin);
    freopen("quadr.out", "w", stdout);

    vector <point> p(4);

    for(point &cur: p) {
        scanf("%d%d", &cur.x, &cur.y);
    }

    do {

        int d0 = dist(p[0], p[1]);
        int d1 = dist(p[1], p[2]);
        int d2 = dist(p[2], p[3]);
        int d3 = dist(p[3], p[0]);
        int diag0 = dist(p[0], p[2]);
        int diag1 = dist(p[1], p[3]);

        if(d0 == d1 && d1 == d2 && d2 == d3 && d3 == d0 && diag0 == diag1 && d0 != 0) {
            return printf("YES"), 0;
        }

    }while(next_permutation(p.begin(), p.end()));

    printf("NO");

    return 0;
}