#include <bits/stdc++.h>
using namespace std;
int main(void){
    long double x,y,r;
    cin>>x>>y>>r;
    x=abs(x);
    y=abs(y);
    x+=r/sqrt(2.0);
    y+=r/sqrt(2.0);
    //cout<<x<<" "<<y<<endl;
    cout<<(int)(x+y+1)<<endl;
    return 0;
}