#include <iostream>
#include <cmath>
using namespace std;
int main(int argc, char** argv) {
  int x, y, r;
  cin >> x >> y >> r;
  if (x < 0) x = -x;
  if (y < 0) y = -y;
  double tmp;
  int ans;
  tmp = x + y + sqrt(2) * r;
  ans = (int)tmp + 1;
  cout << ans << endl;
  return 0;
}