#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <math.h>
using namespace std;

int main() {
    double x,y,r;
    cin >> x >> y >> r;
    if(x < 0)x*=-1;
    if(y < 0)y*=-1;
    x += sqrt(2) * r / 2;
    y += sqrt(2) * r / 2;
    int ans;
    ans = ceil(x + y);
    cout << ans << endl;
    return 0;
}