#include <iostream>
#include <cmath>

using namespace std;

int main() {
    int x, y, r;
    cin >> x >> y >> r;
//    double dis = sqrt(x*x + y*y) + r;
    int b;
    if ((x >= 0 && y >= 0) || (x <= 0 && y <= 0)) {
        // y = -x +b <=>
        b = y + x;
    } else {
        // y = x +b <=>
        b = y - x;
    }
    cout << static_cast<int>(sqrt(2) * r) + abs(b) + 1 << endl;
    return 0;
}