#include<stdio.h>
#include<math.h>
int main(){
  short int x,y,r;
  scanf("%d%d%d",&x, &y, &r);
  int root2;
  root2 = sqrt(2);
  int manhdis;
  manhdis = sqrt(x*x+y*y)+r*root2;
  int i = 0;
  while(i < manhdis){
    i++;
  }
  printf("%d",i);
  return 0;
}