#include <vector> 
#include <list> 
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <queue>
using namespace std;

//conversion
//------------------------------------------
inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v; }
template<class T> inline string toString(T x) { ostringstream sout; sout << x; return sout.str(); }

//math
//-------------------------------------------
template<class T> inline T sqr(T x) { return x * x; }

//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//repetition
//------------------------------------------
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

//constant
//--------------------------------------------
const double EPS = 1e-10;
const double PI = acos(-1.0);

//clear memory
#define CLR(a) memset((a), 0 ,sizeof(a))

//debug
#define dump(x)  cerr << #x << '=' << (x) << endl;
#define debug(x) cerr << #x << '=' << (x) << '('<<'L' << __LINE__ << ')' << ' ' << __FILE__ << endl;

const LL mod = (LL)1e9 + 7;


#define Yes_ cout<<"Yes"<<endl; return 0;
#define No_ cout<<"No"<<endl; return 0;


#define YES_ cout<<"YES"<<endl; return 0;
#define NO_ cout<<"NO"<<endl; return 0;



int main() {
		
	int A, B, C;
	cin >> A >> B >> C;

	int M = max(A, max(B, C));


	while (true) {
		int a = M - A;
		int b = M - B;
		int c = M - C;

		if (a %2== 0) {
			if (b % 2 == 0 && c % 2 == 0) {
				cout <<a/2+ b / 2 + c / 2 << endl;
				return 0;
			}
			else if (b % 2 != 0 && c % 2 != 0) {
				cout <<a/2+ b / 2 + c / 2 + 1 << endl;
				return 0;
			}
		}
		else if (b%2 == 0) {
			if (a % 2 == 0 && c % 2 == 0) {
				cout <<b/2+ a / 2 + c / 2 << endl;
				return 0;
			}
			else if (a % 2 != 0 && c % 2 != 0) {
				cout <<b/2+ a / 2 + c / 2 + 1 << endl;
				return 0;
			}
		}
		else if (c%2 == 0) {
			if (a % 2 == 0 && b % 2 == 0) {
				cout <<c/2+ a / 2 + b / 2 << endl;
				return 0;
			}
			else if (a % 2 != 0 && b % 2 != 0) {
				cout <<c/2+ a / 2 + b / 2 + 1 << endl;
				return 0;
			}
		}
		else if (a % 2 != 0) {
			if (b % 2 != 0 && c % 2 == 0) {
				cout << a / 2 + b / 2 +1+ c / 2 << endl;
				return 0;
			}
			else if (b % 2 == 0 && c % 2 != 0) {
				cout << a / 2 + b / 2 + c / 2 + 1 << endl;
				return 0;
			}
		}
		else if (b % 2 != 0) {
			if (a % 2 != 0 && c % 2 == 0) {
				cout << a / 2 + b / 2 + 1 + c / 2 << endl;
				return 0;
			}
			else if (a % 2 == 0 && c % 2 != 0) {
				cout << a / 2 + b / 2 + c / 2 + 1 << endl;
				return 0;
			}
		}
		else if (c % 2 != 0) {
			if (a % 2 != 0 && b % 2 == 0) {
				cout << a / 2 + b / 2 + 1 + c / 2 << endl;
				return 0;
			}
			else if (a % 2 == 0 && b % 2 != 0) {
				cout << a / 2 + b / 2 + c / 2 + 1 << endl;
				return 0;
			}
		}
		/*else {
			if (a % 2 == 0 && b % 2 == 0&&c%2==0) {
				cout << a / 2 + b / 2 +c/2<< endl;
				return 0;
			}
			if (a % 2 == 0){
				if (b % 2 == 0 && c % 2 == 0) {
					cout << a / 2 + b / 2 + c / 2 << endl;
					return 0;
				}
			}


		}*/


		M++;
	}




}

Measured memory_bytes: 256