#include <bits/stdc++.h>
using namespace std;
const int MAX = 10000;
class Hurry {
  int n, k, m;

 public:
  void read() {
    cin >> n >> k;
    for (m = 1; 5 * m * (m + 1) / 2 + k <= 240; ++m)
      ;
    m--;
    cout << min(n, m);
  }
};
int main() {
  Hurry hu;
  hu.read();
  return 0;
}
