#include <bits/stdc++.h>
using namespace std;
int main() {
  long long x[5];
  for (long long i = 0; i < 3; i++) {
    cin >> x[i];
  }
  sort(x, x + 3);
  long long d = x[0];
  x[1] = x[1] - x[0];
  x[2] = x[2] - x[0];
  if (((x[1] % 3 == 2) && x[2] % 3 == 2) && (x[0] > 0)) {
    d++;
  }
  d += x[1] / 3;
  d += x[2] / 3;
  cout << d << endl;
  return 0;
}
