#include<bits/stdc++.h>
using namespace std;
using Int = long long;
//INSERT ABOVE HERE
Int x,y,r;
Int in(Int a,Int b){
  a=abs(a-x);b=abs(b-y);
  return a*a+b*b<=r*r;
}
Int check(Int a){
  for(Int i=-300;i<=300;i++)
    for(Int j=-300;j<=300;j++)
      if(in(i,j)&&abs(i)+abs(j)>=a) return 0;
  return 1;
}
signed main(){
  cin>>x>>y>>r;
  for(Int a=1;;a++){
    if(check(a)){
      cout<<a<<endl;
      return 0;
    }
  }
  return 0;
}