#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);
    long double k=sqrt(x*x+y*y);
    if(x!=0||y!=0){
        x+=r*x/k;
        y+=r*y/k;
    }else{
        x=r/sqrt(2);
        y=r/sqrt(2);
    }
    cout<<(int)(x+y+1)<<endl;
    return 0;
}