#include <bits/stdc++.h>
#define FOR(i,a,b) for(int i = (a); i < (b); ++i)
#define REP(i,n) FOR(i,0,n)
#define RREP(i,n) for(int i = (n) - 1; (i) >= 0; --i)
#define SZ(n) (int)(n).size()
#define ALL(n) (n).begin(), (n).end()
#define MOD 1000007
#define INF 100000000
using namespace std;
typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PI;


int main() {
	int a[3];
	cin >> a[0] >> a[1] >> a[2];
	int ans = 0;
	REP(i, 101010) {
		sort(a, a + 3);
		int t = a[0];
		a[0] -= t; a[1] -= t; a[2] -= t;
		a[0] += (a[2] - a[1]) / 2;
		a[2] -= a[0] * 2;
		if (a[1] == a[2] && a[1] >= 3) {
			ans++;
			a[2] -= 2;
		}
		ans += t;
	}
	cout << ans << endl;
	return 0;
}