#include<stdio.h>

int main(void){
	int zh[128][128]={0},n,c=0,x,y,i;
	scanf("%d",&n);
	for(i = 1;i <= 2*n;i++){scanf("%d%d",&x,&y);zh[x][y]++;}
	for(x = 1;x <= 100;x++){
		for(y = 1;y <= 100;y++){
			if(zh[x][y] >= 2){c+=(zh[x][y]-1);}
		}
	}
	if(n >= c){printf("YES\n");}else{printf("NO\n");}
	return 0;
}