#include <bits/stdc++.h>
using namespace std;
using namespace chrono;
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#endif

int main() {
    int64_t a, b;
    cin >> a >> b;

    int64_t ans = 0;
    for (int64_t d : {23, 24, 25}) {
        if (a <= d && d <= b) {
            continue;
        }
        ans++;
    }

    cout << ans << endl;

    return 0;
}