#include<iostream>
#include<stdio.h>
#include<math.h>

#define rt2 1.4142
using namespace std;

int main(){

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

    double a = (double)sqrt(x*x+y*y);
    double b = (a+r)*rt2;
    
    cout<< ceil(b)<< endl;
    return 0;
}