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

const int64_t MOD = 1e9 + 7;

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