#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<vector>
#include<map>
#include<queue>
#include<string>
#include<sstream>
#include<cmath>
#include<numeric>
using namespace std;

int main(){

  int x, y, r;
  cin >> x >> y >> r;

  int ans = abs(x) + abs(y) + r*sqrt(2) + 1;

  cout << ans << endl;


  return 0;
}