#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int l, r;
  cin >> l >> r;
  auto f = [](int x) {
    if (x <= 295) return "cpp";
    if (x <= 416) return "rust";
    if (x <= 420) return "python";
    assert(false);
  };
  int ans = 0;
  for (int i = l; i < r; ++i) {
    if (f(i) != f(i + 1)) ++ans;
  }
  cout << ans << '\n';
  return 0;
}