#include <bits/stdc++.h>
using namespace std;

int main()
{
    int x,y,r,m,n;
    cin >> x >> y >> r;

    m = abs(x) + abs(y);
    for(n = 1;; n++){
        if(r < n/sqrt(2)) break;
    }

    cout << m + n << endl;

    return 0;
}