#include <fstream>

using namespace std;
ifstream f("deque.in");
ofstream g("deque.out");
int i,j,v[5000001],k,n,Min;
long long S;
int main()
{f>>n>>k;
for(i=1;i<=k;i++)
f>>v[i];
for(i=k+1;i<=n+1;i++)
{
    Min=10000001;
    for(j=1;j<=k;j++)
        if(v[j]<Min)
            Min=v[j];

    S=S+Min;
    for(j=2;j<=k;j++)
    v[j-1]=v[j];
    f>>v[k];
}
    g<<S;
    return 0;
}