#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

long long c[10002],dp[1001][1001]; int n,k;
long long solve(int right,int idx)
    {
    if(idx==n-1)
        {
        if(right==idx)return dp[right][idx]=c[n-1];
        else if(right==k)return dp[right][idx]=c[n-1];
            else return 0;
    }
    if(dp[right][idx]!=0)return dp[right][idx];
    
        long long x1,x2;
    if(right==k&&idx==right) return dp[right][idx]=solve(0,idx+1)+c[idx];
    else if(right==2*k) return dp[right][idx]=solve(0,idx+1)+c[idx];
    x1=solve(right+1,idx+1);
    x2=c[idx]+solve(0,idx+1);
   return dp[right][idx]=min(x1,x2);     
    
}
int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
  
        cin>>n>>k;
    for(int i=0;i<n;i++)cin>>c[i];
    cout<<solve(0,0);
    return 0;
}