#include <bits/stdc++.h>
using namespace std;
int main() {
  int time[10] = {5, 15, 30, 50, 75, 105, 140, 180, 225, 275};
  int n, k, j = 0;
  cin >> n >> k;
  for (int i = 0; i < n; i++) {
    if (time[i] + k > 240) {
      cout << i;
      return 0;
    } else {
      j++;
    }
  }
  cout << j ? n : 0;
  return 0;
}
