#include <bits/stdc++.h>
using namespace std;
int main() {
  int i, j, k, c = 0, n, s = 0;
  cin >> n >> k;
  for (i = 1; i <= n; i++) {
    s += (5 * i);
    if (s + k <= 240) c++;
  }
  cout << c;
  return 0;
}
