#include <bits/stdc++.h>
using namespace std;
ofstream fo("test.out");
ifstream fi("test.inp");
long long a, b, c, rs;
int main() {
  cin >> a >> b >> c;
  long long s = a + b + c;
  s /= 3;
  if (a > (b + c) * 2)
    rs = b + c;
  else if (b > (a + c) * 2)
    rs = a + c;
  else if (c > (b + a) * 2)
    rs = a + b;
  else
    rs = (a + b + c) / 3;
  cout << rs;
}
