#include <bits/stdc++.h>
using namespace std;
int main() {
  int r, g, b, count = 0, exception = 0;
  cin >> r >> g >> b;
  if (r == 0 || g == 0 || b == 0) exception = 1;
  while (r > 2) {
    r = r - 3;
    count++;
  }
  while (g > 2) {
    g = g - 3;
    count++;
  }
  while (b > 2) {
    b = b - 3;
    count++;
  }
  while (r > 0 && g > 0 && b > 0) {
    r--;
    g--;
    b--;
    count++;
  }
  if (((r == 2 && g == 2) || (g == 2 && b == 2) || (r == 2 && b == 2)) &&
      (exception == 0))
    count++;
  cout << count << endl;
}
