#include<iostream>
#define c 3
using namespace std;
//23,24,25
int main()
{
	int A, B;
	
		int count = 0;
		cin >> A;
		cin >> B;
		for (int i = A;i <= B;i++)
		{
			if (23 <= i&& i <= 25)
			{
				count++;
			}
		}
		cout << c-count;
		
	return 0;
}