#include <bits/stdc++.h> 

using namespace std;
typedef long long ll;

int main() {
    double x, y, r;
    cin >> x >> y >> r;
    x = abs(x);
    y = abs(y);

    // double large = max(x, y);
    // double small = min(x, y);
    // int term = ceil(large + 0.5 * r);

    int ans = (int)(x + r * 0.707 + y + r * 0.707) + 1;
    cout << ans << endl;
}