#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <cmath>
#include <iomanip>
#include <stack>
#include <queue>
#include <numeric>
#include <map>
#include <unordered_map>
#include <set>
#include <fstream>
#include <chrono>
#include <random>
#include <bitset>
#define rep(i,n) for(int i=0;i<(n);i++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) ((int)(x).size())
#define pb push_back
#define mod 1000000007
using ll = long long;
using namespace std;
ll gcd(ll a, ll b) {return b?gcd(b,a%b):a;}
ll lcm(ll a, ll b) {return a/gcd(a,b)*b;}

int main(){
  int A, B, C; cin >> A >> B >> C;
  if(A>C){
    int tmp = A;
    A = C;
    C = tmp;
  }
  int ans = 0;
  int ans1 = abs(A-C);
  int ans2=0;
  if(A<B && B<C) ans2 = 0;
  else{
    ans2 += B-(C-1);
    B = min(C-1,B);
    ans2 += max(0,A-(B-1));
  }
  ans = min(ans1,ans2);
  cout << ans << endl;
  return 0;
}