#include <bits/stdc++.h>
using namespace std;
int main(){
	int a,b,year,sum=0;
	cin>>a>>b;
	int z=1899,day=1;
	while(z!=b)
	{
		z++;
		if(z%4==0&&z%100!=0||z%400==0){
			
			if(z>=a){
			if((day+306+29)%7==6||(day+306+29)%7==0){
					sum++;	
			}				
			}
			day=day+366%7;
			}
		else{
		
			if(z>=a){
						if((day+334)%7==6||(day+334)%7==0){
				sum++;	

			}	
			}

		day=day+365%7;
			}
						
			
		}
	cout<<sum;	 
	return 0;		

	}