#include <iostream>
#include <algorithm>
#include <string>
#include <cstring>
using namespace std;

#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)
#define SQR(X) ((X)*(X))

typedef long long ll;
typedef unsigned long long ull;
typedef long double lb;
/* ここからが本編 */

int main(void)
{
   int i,j;
   int x,y,r;
   int dis;
   cin >> x >> y >> r;
   if(x < 0) x *= -1;
   if(y < 0) y *= -1;
   dis = (int)(sqrt((double)2)*r);
   if(dis < sqrt( (double)2)*r  ) dis++;

   cout << dis+x+y << endl;
   
   return 0;
}