#include <bits/stdc++.h>
int main() {
  unsigned int a, b, c;
  scanf("%u%u%u", &a, &b, &c);
  if (((a % 3 + b % 3 + c % 3 == 4 && (a == 0 || b == 0 || c == 0)) ||
       a % 3 + b % 3 + c % 3 == 3) &&
      (a % 3) * (b % 3) * (c % 3) == 0) {
    printf("%u\n", (a + b + c) / 3 - 1);
  } else
    printf("%u\n", (a + b + c) / 3);
}
