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

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

    x=(x<0)?x*(-1):x;
    y=(y<0)?y*(-1):y;

    ans=x+r*sqrt(2)/2+y+r*sqrt(2)/2+1;
    cout << (int)ans <<endl;

    return 0;
}