#include <stdio.h>
#include <string.h>
#include <ctype.h>

int main(void){
	char str[100];
	scanf("%s",str);
	
	int i = 0;
	while(i != (int)strlen(str)){
		printf("i：%d　文字：%c；\n",i,str[i]);
		if (isupper(str[i])){
			printf("No");
			return 0;
		}
		i++;
		printf("i：%d　文字：%c；\n",i,str[i]);
		if(str[i] != ' '){
			printf("No");
			return 0;
		}
		i++;
	}
	printf("Yes");
}