#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;

#define rep(i, n) REP(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define MSG(a) cout << #a << " " << a << endl;
#define REP(i, x, n) for (int i = x; i < n; i++)
#define OP(m) cout << m << endl
typedef long long ll;
typedef unsigned long long ull;

int main()
{
    double xa, ya, xb, yb, xc, yc, xd, yd;
    while (cin >> xa >> ya >> xb >> yb >> xc >> yc >> xd >> yd)
    {
        if (abs((yb - ya) * (yd - yc) + (xb - xa) * (xd - xc)) < 0.0000000001)
            OP("YES");
        else
            OP("NO");
    }
    return 0;
}
