import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.HashSet;
import java.io.FilterInputStream;
import java.io.BufferedInputStream;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author khokharnikunj8
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        ScanReader in = new ScanReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        CFoursegment solver = new CFoursegment();
        solver.solve(1, in, out);
        out.close();
    }

    static class CFoursegment {
        public void solve(int testNumber, ScanReader in, PrintWriter out) {
            int[][] xy = new int[4][4];
            for (int i = 0; i < 4; i++) {
                for (int j = 0; j < 4; j++) {
                    xy[i][j] = in.scanInt();
                }
            }
            HashSet<Integer> set = new HashSet<>();
            int cur_x = xy[0][2];
            int cur_y = xy[0][3];
            set.add(0);
            out:
            for (int j = 0; j < 3; j++) {
                for (int i = 0; i < 4; i++) {
                    if (!set.contains(i)) {
                        if (xy[i][0] == cur_x && xy[i][1] == cur_y) {
                            set.add(i);
                            cur_x = xy[i][2];
                            cur_y = xy[i][3];
                            continue out;
                        } else if (xy[i][2] == cur_x && xy[i][3] == cur_y) {
                            set.add(i);
                            cur_x = xy[i][0];
                            cur_y = xy[i][1];
                            continue out;
                        }
                    }
                }
                out.println("NO");
                return;
            }
            if (cur_x == xy[0][0] && cur_y == xy[0][1]) {
                out.println("YES");
            } else {
                out.println("NO");
            }
        }

    }

    static class ScanReader {
        private byte[] buf = new byte[4 * 1024];
        private int index;
        private BufferedInputStream in;
        private int total;

        public ScanReader(InputStream inputStream) {
            in = new BufferedInputStream(inputStream);
        }

        private int scan() {
            if (index >= total) {
                index = 0;
                try {
                    total = in.read(buf);
                } catch (Exception e) {
                    e.printStackTrace();
                }
                if (total <= 0) return -1;
            }
            return buf[index++];
        }

        public int scanInt() {
            int integer = 0;
            int n = scan();
            while (isWhiteSpace(n)) n = scan();
            int neg = 1;
            if (n == '-') {
                neg = -1;
                n = scan();
            }
            while (!isWhiteSpace(n)) {
                if (n >= '0' && n <= '9') {
                    integer *= 10;
                    integer += n - '0';
                    n = scan();
                }
            }
            return neg * integer;
        }

        private boolean isWhiteSpace(int n) {
            if (n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1) return true;
            else return false;
        }

    }
}

