#include <bits/stdc++.h>
using namespace std;

int C[ 3 ];

void Cnt( int &iA, int &iB, const int X, const int iNum )
{
	if( X > iNum )
		iA += ( X - iNum ) / 2;
	else if( X < iNum )
		iB += ( iNum - X );
}

bool bChk( const int R, const int G, const int B,
		const int iNum )
{
int iA;
int iB;

	iA = 0;
	iB = 0;
	Cnt( iA, iB, R, iNum );
	Cnt( iA, iB, G, iNum );
	Cnt( iA, iB, B, iNum );

	return (bool) ( iA >= iB );
}

bool bChk( const int iNum )
{
	return bChk( C[ 0 ], C[ 1 ], C[ 2 ], iNum );
}

int main()
{
int R;
int G;
int B;
int iNum;
int iTop;
int iBtm;

	cin >> C[ 0 ];
	cin >> C[ 1 ];
	cin >> C[ 2 ];

	sort( C, C + 3 );

	iBtm = C[ 0 ];
	iNum = C[ 1 ];
	iTop = C[ 2 ];

	while( iBtm + 1 < iTop )
	{
		if( bChk( iNum ) )
			iBtm = iNum;
		else
			iTop = iNum;

		iNum = ( iBtm + iTop ) / 2;
	}

	if( bChk( iTop ) )
		cout << iNum << endl;
	else
		cout << iBtm << endl;

	return 0;
}