#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>

int main() {

  long i, j, k;
  long ans[3];
  long count = 0;
  std::string str;
  std::vector<long> v;
  long temp;
  
  double x, y, r;

  std::cin >> x >> y >> r;

  std::cout << (int)((abs(x)+abs(y))+sqrt(2)*r)+1 << std::endl;
  return 0;  
}