#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;
typedef long long ll;
int main(){
    int i,n,k; cin >> n >> k;
    vector<ll> a;
    ll ans = 0;
    for(i=0;i<n;i++){
        ll x; cin >> x;
        if(x<=k){
            a.push_back(x);
        }else if(x&1){
            a.push_back(-1);
            ans += (x + 1)/2;
        }else{
            a.push_back(0);
            ans += x/2;
        }
    }
    sort(a.rbegin(),a.rend());
    for(i=0;i<n;i+=2) ans += a[i];
    cout << ans << "\n";
}