C++ :

#include<bits/stdc++.h>
using namespace std;
int a,b;
int main()
{
//	freopen("1.in","r",stdin);
//	freopen("1.out","w",stdout);
	cin>>a>>b;
	a--; 
	int s1=a/4-a/100+a/400;
	int s2=b/4-b/100+b/400;
	cout<<s2-s1;
	return 0;
}