#include <bits/stdc++.h>
using namespace std;
int main() {
  int a[3] = {-1}, b, c, i, j, temp, sum = 0;
  cin >> a[0] >> a[1] >> a[2];
  for (i = 0; i < 2; i++)
    for (j = 0; j <= 2 - i - 1; j++) {
      if (a[j] > a[j + 1]) {
        temp = a[j];
        a[j] = a[j + 1];
        a[j + 1] = temp;
      }
    }
  sum = a[0] + (a[1] - a[0]) / 3 + (a[2] - a[0]) / 3;
  if ((a[2] - a[0]) % 3 == 2 && (a[1] - a[0]) % 3 == 2 && a[0] != 0) sum += 1;
  cout << sum;
  return 0;
}
