#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
#define rep(i,n) for(int i=0;i<n;i++)

signed main() {
  double x,y,r;
  cin>>x>>y>>r;
  int temp=0;
  for(int i=1;i<=500;i++){
    if(pow(r*r*2,0.5)<i){
      temp=i;
      break;
    }
  }
  cout<<temp+x+y<<endl;
  return 0;
}