import java.io.*;
import java.util.*;
class line {
public static void main(String[] args) {
	InputReader s=new InputReader(System.in);
	int n=s.nextInt();
    int a[][]=new int[n][2];
    for (int i=0;i<n;i++) {
        a[i][0]=s.nextInt();
        a[i][1]=s.nextInt();
    }
    boolean ans=true;
    if(a[0][0]==a[1][0]){
        for (int i=0;i<n-1;i++) {
            if(a[i][0]!=a[i+1][0]){
                ans=false;
                break;
            }
        }
    }
    else if(a[0][1]==a[1][1]){        
        for (int i=0;i<n-1;i++) {
            if(a[i][1]!=a[i+1][1]){
                ans=false;
                break;
            }
        }
    }
    else {
        ans=false;
    }
	
	System.out.println(ans==true?"YES":"NO");


	}	
	static class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private SpaceCharFilter filter;
 
    public InputReader(InputStream stream) {
        this.stream = stream;
    }
 
    public static boolean isWhitespace(int c) {
        return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }
 
    public int read() {
        if (numChars == -1)
            throw new InputMismatchException();
        if (curChar >= numChars) {
            curChar = 0;
            try {
                numChars = stream.read(buf);
            } catch (IOException e) {
                throw new InputMismatchException();
            }
            if (numChars <= 0)
                return -1;
        }
        return buf[curChar++];
    }
 
    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 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 String nextToken() {
        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 boolean isSpaceChar(int c) {
        if (filter != null)
            return filter.isSpaceChar(c);
        return isWhitespace(c);
    }
 
    public interface SpaceCharFilter {
        public boolean isSpaceChar(int ch);
    }
}
}