#include<bits/stdc++.h>
#define rep(i, x) for(ll i = 0; i < x; i++)
#define rep2(i, x) for(ll i = 1; i <= x; i++)
#define all(a) (a).begin(),(a).end()
using ll = long long;
using ld = long double;
using namespace std;
signed main() {
    ll n, m, cnt = 3; cin >> n >> m;
	for (int h = n; h <= m; h++) {
		if (h >= 23 && h <= 25) { cnt--; }
	}
	cout << cnt << endl;
	return 0;
}