#include <bits/stdc++.h>   using namespace std;   int n, k, l, r, mid, a;   int main() {     cin >> n >> k;     a = 240 - k;     l = 0;     r = n + 1;     while (r - l > 1) {       mid = (r + l) / 2;       if (5 * (mid * (mid + 1) / 2) > a) {         r = mid;       } else {         l = mid;       }     }     cout << l << endl;     return 0;   }   