ac

#include <bits/stdc++.h>
using namespace std;
int n;
int main()
{
cin >> n;
int a[n];
a[1]=0;
for (int i = 2; i <= n; i++)
{
a[i] = i - 1;
for (int j = 2; i - j * j >= 1; j++)
{
a[i] = min(a[i], a[i - j * j] + j + 1);
}
}
cout << a[n];
return 0;
}