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

#include <iostream>
#include <vector>
#include <algorithm>

int main() {

  long i;

  long a, b, s;
  long a_s;
  long b_s;
  long ans;

  std::cin >> a >> b >> s;

  a_s = abs(a-s);
  b_s = abs(b-s);

  if( a == 0 ) {
    ans = 2 * s;
  }
  else {
    if(a_s > b_s) {
      ans = b_s + abs(a-b) + a;
    }
    else {
      ans = a_s + s;
    }
  }

  std::cout << ans << std::endl;
  
  return 0;
}