#include <bits/stdc++.h>
using namespace std;
int main() {
  int r, g, b;
  int r1, g1, b1;
  int a[4];
  while (cin >> r >> g >> b) {
    r1 = r / 3;
    g1 = g / 3;
    b1 = b / 3;
    int ans = r1 + g1 + b1;
    if (r && g && b) {
      a[0] = r % 3;
      a[1] = g % 3;
      a[2] = b % 3;
      sort(a, a + 3);
      if (a[0] == 0 && a[1] == 2)
        ans++;
      else
        ans += a[0];
    }
    cout << ans << endl;
  }
  return 0;
}
