#include <iostream>
#include <stdlib.h>
#include <math.h>
using namespace std;

int main(){
  int x, y, r;

  cin >> x >> y >> r;
  /* UFOと境界の接点座標は(x + r(√2/2), y + r(√2/2)) (第一象限のとき)*/
  double mht_dist = ceil((double)abs(x) + (double)(abs(y)) + sqrt(2)*(double)r);
  cout << mht_dist << endl;
  return 0;
}