///==================================================///
///                HELLO WORLD !!                    ///
///                  IT'S ME                         ///
///               BISHAL GAUTAM                      ///
///         [ bsal.gautam16@gmail.com ]              ///
///==================================================///
#include<bits/stdc++.h>
#define X first
#define Y second
#define mpp make_pair
#define nl printf("\n")
#define SZ(x) (int)(x.size())
#define pb(x) push_back(x)
#define pii pair<int,int>
#define pll pair<ll,ll>
///---------------------
#define S(a) scanf("%d",&a)
#define P(a) printf("%d",a)
#define SL(a) scanf("%lld",&a)
#define S2(a,b) scanf("%d%d",&a,&b)
#define SL2(a,b) scanf("%lld%lld",&a,&b)
///------------------------------------
#define all(v) v.begin(),v.end()
#define CLR(a) memset(a,0,sizeof(a))
#define SET(a) memset(a,-1,sizeof(a))
#define fr(i,a,n) for(int i=a;i<=n;i++)
using namespace std;
typedef long long ll;

///  Digit     0123456789012345678 ///
#define MX     22
#define inf    200000001000000LL
#define MD     1000000007
#define eps    1e-9
///===============================///

ll ar[50];
int n,i,j,k,lim,pre[33];
int main() {
    S2(n,k);
    for(i=0;i<n;i++)SL(ar[i]);
    lim=(1<<n)-1;
    for(i=0; i<n; i++) {
        pre[i]=(1<<i);
        for(j=i-1; j>=max(0,i-k); j--) {
            pre[i]|=(1<<j);
        }
        for(j=i+1; j<=min(n-1,i+k); j++) {
            pre[i]|=(1<<j);
        }
    }
    //cout<< "Ses\n";
    ll mn=inf;
    for(i=0; i<=lim; i++) {
        ll sm=0;
        int msk=0;
        for(j=0; j<n; j++) {
            if( i&(1LL<<j) ){
                sm+=ar[ j ];
                msk^=pre[i];
            }
        }
        if( msk==lim ){
            mn=min(mn,sm);
        }
    }

    printf("%lld\n",mn);

    //assert(n<=20);
    return 0;
}