#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n);i++)
#define sz(x) int(x.size())
typedef long long ll;
typedef pair<int,int> P;

ll r,g,b;

bool ok(ll n) {
  ll s = 0,t = 0;
  if (r<n) s += (n-r);
  if (g<n) s += (n-g);
  if (b<n) s += (n-b);
  if (r>=n) t += (r-n)/2;
  if (g>=n) t += (g-n)/2;
  if (b>=n) t += (b-n)/2;
  return t >= s;
}

int main(){

  cin >> r >> g >> b;
  ll left = 0, right = 1e8;
  while (right - left > 1) {
    ll mid = (left + right) / 2;
    if ( ok(mid) ) left = mid;
    else right = mid;
  }
  cout << left << endl; 
  return 0;
}