#include <bits/stdc++.h>
using namespace std;
long long dp[2001][2001];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  ;
  vector<long long> v(3);
  cin >> v[0] >> v[1] >> v[2];
  sort(v.begin(), v.end());
  long long x1 = v[0];
  long long x2 = v[1];
  long long x3 = v[2];
  if (x3 >= 2 * (x1 + x2)) {
    cout << x1 + x2, cout << "\n";
  } else
    cout << (x1 + x2 + x3) / 3, cout << "\n";
}
