#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;

int x, y, r;

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