#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define ld long double
#define vi vector<int>
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define pii pair<int,int>
#define pll pair<ll,ll>
#define vii vector<pii >
#define vll vector<ll >
#define cps CLOCKS_PER_SEC
#define eb emplace_back
#define rep(i, begin, end) for (__typeof(end) i = (begin) - ((begin) > (end)); i != (end) - ((begin) > (end)); i += 1)
#define all(a) (a).begin(), (a).end()
#define sz(a) int((a).size())
#define print(s) cout<<#s<<" : ";for(auto i:(s))cout<<i<<" ";cout<<"\n";
#define slld(t) scanf("%lld",&(t))
#define sd(t) scanf("%d",&(t))

ll dp[3005][3005];
int c[10005];
ll DP(int i,int j, int k)
{
    if(i>j || i<0 || j<0)
        return 0;
    if(dp[i][j]>=0)
        return dp[i][j];
    ll ans = 1e18;
    for(int l = i;l<=j;l++)
    {
        ans = min(ans, DP(i,l-k-1,k)+DP(l+k+1,j,k)+c[l]);
    }
    dp[i][j] = ans;
    return ans;
}
int main()
{
    int n,k;
    sd(n),sd(k);
    for(int i = 1;i<=n;i++)
        sd(c[i]);
    for(int i = 1;i<=n;i++)
        for(int j = i;j<=n;j++)
            dp[i][j] = -1;
    for(int i = 1;i<=n;i++)
        for(int j = i;j<=n;j++)
            DP(i,j,k);    
    cout<<DP(1,n,k);    
}