#include<fstream>
#include<limits.h>
#include<vector>
using namespace std;
ifstream cin("deque.in");
ofstream cout("deque.out");
vector <int> a;
int  n, k, i, s=0;
int man=INT_MAX;

int main()
{

cin>>n>>k;
for(i=1; i<=n; i++)
  {
      cin>>a[i];
  }
  for(i=1; i<=i+k; i++)
  {if(man>a[i])
  {
      man=a[i];
      s=s+a[i];
  }}
  cout<<s;

cin.close();
cout.close();
return 0;
}