#include <stdio.h>
int main(void){
	int start,finish;
	scanf("%d%d",&start,&finish);
	
	int count = 3;
	for(int i = start;i <= finish;i ++){
		if(i == 23 || i == 24 || i == 25){
			count--;
		}
	}
	printf("%d",count);
}