#include <cmath>
#include <cstdlib>
#include <cstdio>
#include <climits>
#include <functional>
#include <bitset>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <sstream>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <set>
#include <map>
using namespace std;

typedef long long ll;
int n, k;
vector<int> c;
ll f(int s) {
    if (s==((1<<n)-1)) return 0;
    ll r=INT_MAX;
    for (int i=0; i<n; ++i) {
        if (!(s&1<<i)) {
            int s2=s;
            s2|=(1<<i);
            if (i==0) {
                for (int j=1; j<=k; ++j) s2|=(1<<i+j);
            } else if (i==n-1) {
                for (int j=1; j<=k; ++j) s2|=(1<<i-j);
            } else {
                for (int j=1; j<=k; ++j) {
                    s2|=(1<<i+j);
                    s2|=(1<<i-j);
                }
            }
            r=min(r, c[n-1-i]+f(s2));
        }
    }
    return r;
}
int main() {
    ll r=0;
    cin>>n>>k;
    c.resize(n);
    for (int i=0; i<n; ++i) cin>>c[i];
    cout<<f(0)<<endl;
    return 0;
}