#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return true; } return false; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return true; } return false; }
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define mp make_pair
#define si(x) int(x.size())
const int mod=998244353,MAX=300005,INF=15<<26;

int main(){
    
    std::ifstream in("text.txt");
    std::cin.rdbuf(in.rdbuf());
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    ll N,K;cin>>N>>K;
    vector<ll> A,B;
    ll pass=0,ans=0;
    for(int i=0;i<N;i++){
        ll x;cin>>x;
        if(x<=K) A.push_back(x);
        else{
            if(x%2==0){
                ans+=x/2;
                pass++;
            }else{
                B.push_back(x);
            }
        }
    }
    sort(all(A));
    reverse(all(A));
    for(int i=0;i<si(A);i+=2) ans+=A[i];
    bool f=((si(A)+pass)&1);
    for(ll x:B){
        if(x%2==0) ans+=x/2;
        else{
            if(!f){
                ans+=x/2;
            }else{
                ans+=(x+1)/2;
            }
            f^=1;
        }
    }
    cout<<ans<<endl;
}