#include <iostream>
#include <fstream>
#include <deque>

using namespace std;
int s=0, i, j, v[5000000], k, n;

int main()
{
    int min;
    ifstream f("deque.in");
    ofstream g("deque.out");
    f>>n;
    f>>k;
    for(i=1; i<=n; i++)
        f>>v[i];
    for(i=1; i<=n; i++)
        {min=v[i];
         for(j=i; j<=k; j++)
            if(v[j]<min)
                min=v[j];
        s=s+min;

        if(k<=n)
            k++;
        }
    g<<s;





}