#include <bits/stdc++.h>
using namespace std;
const int N = 1000010, inf = 1000000007;
long long a, b, c;
int main() {
  scanf("%I64d %I64d %I64d", &a, &b, &c);
  if (a > b) swap(a, b);
  if (b > c) swap(b, c);
  if (a > b) swap(a, b);
  if (c > 2ll * (a + b))
    printf("%I64d\n", a + b);
  else
    printf("%I64d\n", (a + b + c) / 3);
  return 0;
}
