#include <stdio.h>
void main(void){
	int previousVer[3] = {0,0,0};
	scanf("%d.%d.%d",previousVer[0],previousVer[1],previousVer[2]);
	int newVer[3] = {0,0,0};
	scanf("%d.%d.%d",newVer[0],newVer[1],newVer[2]);
	if(previousVer[0] == newVer[0]){
		printf("YES");
	}else{
		printf("NO");
	}
}