#include <bits/stdc++.h>
using namespace std;
 
int main(){
  int count =0;
  int a, b, c;
  cin >> a >> b >> c;
  while(true){
    int d = count;
    for(int i=0;i<3;i++){
      if(i==0)a--;
      else if(i==1)b-=1;
      else if(i==2)c--;
      count++;
      if(a==b||a==c||b==c||a==0||b==0||c==0){
        if(i==0)a++;
        else if(i==1)b++;
        else c++;
        count--;
        break;
  
      } 
    
    
    }

    if(count == d) break;
  }
  cout << count;
}