``` #include <bits/stdc++.h> using namespace std; int main() { int h,r; cin >> h >> r; double v = 3.14159 * (r * r * h) / 1000; //这里是ml / 1000 ==》 l double count = 0; int t = 0; if ( v >= 20 ) { cout << 1; return 0; } while ( count < 20 ) { count = count + v; t++; } cout << t; return 0; } ```