#include <bits/stdc++.h>
using namespace std;
const int md = 1000000007;
const int maxn = 101010;
const long long inf = 2020202020202020202LL;
int main() {
  long long a[3];
  for (int i = 0; i < 3; i++) cin >> a[i];
  sort(a, a + 3);
  long long d = a[0] + a[1] + a[2];
  d = d / 3;
  long long e = a[1] + a[1] + a[0] + a[0];
  long long z = e / 2;
  if (a[2] > e)
    cout << z;
  else
    cout << d;
  return 0;
}
