#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  scanf("%d %d", &n, &k);
  int a = 240 - k, cnt = 0;
  int arr[] = {5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60};
  int ans = 0;
  for (int i = 0; i < n; i++) {
    ans += arr[i];
    if (ans > a) break;
    cnt++;
  }
  cout << cnt << endl;
  return 0;
}
