#include <stdio.h>
#include <algorithm>
using namespace std;

int main()
{
	int R,G,B;
	scanf ("%d %d %d",&R,&G,&B);

	int l = 0, r = 10000001;
	while (l + 1 < r){
		int m = (l + r) / 2;

		int u = 0, v = 0;
		for (int x : {R,G,B}){
			if (x - m < 0) u += m - x;
			else v += (x - m) / 2;
		}

		if (u <= v) l = m;
		else r = m;
	}

	printf ("%d\n",l);

	return 0;
}