#include <cstdio>
#include <algorithm>

using namespace std;

int c[3];

bool check(int k) {
  int pos = 0;
  int neg = 0;
  for (int i = 0; i < 3; i++) {
    if (c[i] >= k)
      pos += c[i] - k;
    else
      neg += k - c[i];
  }
  return pos >= 2 * neg;
}

int solve() {
  int hi = 10000000+1;
  int lo = 0;
  while (hi - lo > 1) {
    int mi = (hi + lo) / 2;
    if (check(mi))
      lo = mi;
    else
      hi = mi;
  }
  return lo;
}

int main(int argc, char *argv[])
{
  scanf(" %d %d %d", c, c+1, c+2);
  sort(c, c+3);
  printf("%d\n", solve());
  return 0;
}