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

using ll=long long;
ll mod=1000000007;
ll INF=1LL<<60;

int main() {
	int A,B,cnt=0;
	cin >> A >> B;
	for(int e : {23,24,25})if(e<A || B<e)cnt++;
	cout << cnt << endl;
}