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

int main(void){
	int x,y,r;
	double masu;
	int dis;
	scanf("%d %d %d", &x, &y, &r);
	x = abs(x);
	y = abs(y);
	
	masu = 1.0*r/sqrt(2);
	masu *= 2;
	
	dis = x+y+(int)ceil(masu);
	
	printf("%d\n", dis);
	return 0;
}