#include <bits/stdc++.h>
using namespace std;

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);  
	int a, b;
	cin >> a >> b;
	if(a <= 23) {
		if(b >= 25) {
			cout << 0 << endl;
			return 0;
		} else {
			if(b == 24) cout << 1 << endl;
			else if(b == 23) cout << 2 << endl;
			else cout << 3 << endl;
			return 0;
		}
	} else {
		if(a == 24) {
			if(b == 24) {
				cout << 2 << endl;
				return 0;
			}
			if(b >= 25) {
				cout << 1 << endl;
				return 0;
			}
		} else {
			if(a == 25) cout << 2 << endl;
			else cout << 3 << endl;
			return 0;
		}
	}
	
	return 0;	
}