#include <bits/stdc++.h>
int cmp(const void *a, const void *b) { return *(int *)b - *(int *)a; }
int main() {
  long long int a[4];
  for (int i = 0; i < 3; i++) {
    scanf("%I64d", a + i);
  }
  qsort(a, 3, sizeof(long long int), cmp);
  if (a[0] > 2 * (a[1] + a[2])) {
    printf("%I64d\n", a[1] + a[2]);
  } else {
    printf("%I64d\n", (a[0] + a[1] + a[2]) / 3);
  }
}
