#include <iostream>
#include <math.h>
using namespace std;
int main(int argc, char* argv[])
{
	double x,y,r;
	cin>>x>>y>>r;
	double x1=abs(x)+abs(y)+sqrt(2.0)*r;
	if (x1==(int)x1){
		cout<<x1<<endl;
	}else{
		cout<<(int)x1+1<<endl;
	}
	return 0;
}