
import java.io.*;
import java.math.*;
import java.util.*;

import static java.util.Arrays.fill;
import static java.lang.Math.*;
import static java.util.Arrays.sort;
import static java.util.Collections.sort;


public class C14 
{

	public static int mod = 1000000007;
	public static long INF = (1L << 60);
	static FastScanner2 in = new FastScanner2();
	static OutputWriter out = new OutputWriter(System.out);
	static class Pair implements Comparable<Pair>
	{
		int x,y;
		Pair(int x,int y)
		{
			this.x=x;
			this.y=y;
		}
		@Override
		public int hashCode()
		{
			final int prime = 31;
			int result = 1;
			result = prime * result + x;
			result = prime * result + y;
			return result;
		}
		@Override
		public boolean equals(Object obj) 
		{
			if (this == obj)
				return true;
			if (obj == null)
				return false;
			if (getClass() != obj.getClass())
				return false;
			Pair other = (Pair) obj;
			if (x != other.x)
				return false;
			if (y != other.y)
				return false;
			return true;
		}
		@Override
		public int compareTo(Pair o)
		{
			// TODO Auto-generated method stub
			if(this.y==o.y)
				return this.x-o.x;
			return this.y-o.y;
		}
		
		
	}
	public static void main(String[] args) 
	{

		TreeSet<Pair> set=new TreeSet<>();
		for(int i=1;i<=4;i++)
		{
			int x1=in.nextInt();
			int y1=in.nextInt();
			int x2=in.nextInt();
			int y2=in.nextInt();
			Pair p1=new Pair(x1, y1);
			Pair p2=new Pair(x2, y2);
			set.add(p1);
			set.add(p2);
		}
		if(set.size()!=4)
		{
			System.out.println("NO");
			return;
		}
		Pair[] arr=new Pair[5];
		int i=1;
		for(Pair p : set)
		{
			arr[i++]=p;
		}
		if(arr[1].x==arr[3].x&&arr[2].x==arr[4].x&&arr[1].y==arr[2].y&&arr[3].y==arr[4].y)
		{
			out.println("YES");
			out.flush();
			return;
		}
		out.println("NO");
		out.close();

	}
	
	public static long pow(long x, long n) 
	{
		long res = 1;
		for (long p = x; n > 0; n >>= 1, p = (p * p)) 
		{
			if ((n & 1) != 0) 
			{
				res = (res * p);
			}
		}
		return res;
	}
	
	public static long pow(long x, long n, long mod) 
	{
		long res = 1;
		for (long p = x; n > 0; n >>= 1, p = (p * p) % mod) 
		{
			if ((n & 1) != 0) 
			{
				res = (res * p % mod);
			}
		}
		return res;
	}

	public static long gcd(long n1, long n2)
	{
		long r;
		while (n2 != 0) 
		{
			r = n1 % n2;
			n1 = n2;
			n2 = r;
		}
		return n1;
	}

	public static long lcm(long n1, long n2) 
	{
		long answer = (n1 * n2) / (gcd(n1, n2));
		return answer;
	}

	static class FastScanner2 
	{
		private byte[] buf = new byte[1024];
		private int curChar;
		private int snumChars;

		public int read() 
		{
			if (snumChars == -1)
				throw new InputMismatchException();
			if (curChar >= snumChars) 
			{
				curChar = 0;
				try 
				{
					snumChars = System.in.read(buf);
				} catch (IOException e) 
				{
					throw new InputMismatchException();
				}
				if (snumChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}

		public String nextLine() 
		{
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do 
			{
				res.appendCodePoint(c);
				c = read();
			} 
			while (!isEndOfLine(c));
			return res.toString();
		}

		public String nextString() 
		{
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do 
			{
				res.appendCodePoint(c);
				c = read();
			} 
			while (!isSpaceChar(c));
			return res.toString();
		}

		public long nextLong()
		{
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			long res = 0;
			do 
			{
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} 
			while (!isSpaceChar(c));
			return res * sgn;
		}

		public int nextInt() 
		{
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			int res = 0;
			do 
			{
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} 
			while (!isSpaceChar(c));
			return res * sgn;
		}

		public int[] nextIntArray(int n)
		{
			int[] arr = new int[n];
			for (int i = 0; i < n; i++) 
			{
				arr[i] = nextInt();
			}
			return arr;
		}

		public long[] nextLongArray(int n)
		{
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) 
			{
				arr[i] = nextLong();
			}
			return arr;
		}

		private boolean isSpaceChar(int c)
		{
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		private boolean isEndOfLine(int c) 
		{
			return c == '\n' || c == '\r' || c == -1;
		}
	}

	static class InputReader 
	{
		public BufferedReader reader;
		public StringTokenizer tokenizer;

		public InputReader(InputStream inputstream) 
		{
			reader = new BufferedReader(new InputStreamReader(inputstream));
			tokenizer = null;
		}

		public String nextLine() 
		{
			String fullLine = null;
			while (tokenizer == null || !tokenizer.hasMoreTokens())
			{
				try 
				{
					fullLine = reader.readLine();
				} catch (IOException e)
				{
					throw new RuntimeException(e);
				}
				return fullLine;
			}
			return fullLine;
		}

		public String next()
		{
			while (tokenizer == null || !tokenizer.hasMoreTokens()) 
			{
				try 
				{
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) 
				{
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}

		public long nextLong() 
		{
			return Long.parseLong(next());
		}

		public int[] nextIntArray(int n) 
		{
			int a[] = new int[n];
			for (int i = 0; i < n; i++) 
			{
				a[i] = nextInt();
			}
			return a;
		}

		public long[] nextLongArray(int n)
		{
			long a[] = new long[n];
			for (int i = 0; i < n; i++) 
			{
				a[i] = nextLong();
			}
			return a;
		}

		public int nextInt() 
		{
			return Integer.parseInt(next());
		}
	}

	static class OutputWriter 
	{
		private final PrintWriter writer;

		public OutputWriter(OutputStream outputStream) 
		{
			writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
		}

		public OutputWriter(Writer writer)
		{
			this.writer = new PrintWriter(writer);
		}

		public void print(Object... objects)
		{
			for (int i = 0; i < objects.length; i++) 
			{
				if (i != 0)
					writer.print(' ');
				writer.print(objects[i]);
			}
		}

		public void println(Object... objects)
		{
			print(objects);
			writer.println();
		}

		public void close() 
		{
			writer.close();
		}

		public void flush() 
		{
			writer.flush();
		}
	}

}