#include <fstream>

using namespace std;
ifstream f ("deque.in");
ofstream g ("deque.out");
void pune (int i )
{int n,a[100],b[100],u,p;
    while (n>0&&a[b[u]]>a[i])
    {
        u--;
    }
    u++;
    b[u]=i;
}
int n,i,k,a[100],b[100],p,x,s;
int main()
{f>>n>>k;
p=1;
   for(i=1;i<=n;i++);
   f>>a[i];
   for(i=1;i<=k;i++)
   pune(i);
   for(i=k;i<n;i++)
   {
       pune(i);
       s+=b[p];
       if(i-b[p]==k)
       p++;
   }
   g<<s;
    return 0;
}