#include<stdio.h>
#include<stdlib.h>

struct Elem{
	int value;
	int before;
	struct Elem *prev, *next;
};

class Deque{
	public:
		struct Elem *pHead, *pTail;		

		Deque(){
			pHead = new struct Elem;
			pTail = new struct Elem;
			pHead = NULL;
			pTail = NULL;
		}

		~Deque(){}

		void addBack(int info, int ant) {
            struct Elem *paux;

            paux = new struct Elem;
            paux->value = info;
			paux->before = ant;
            paux->prev = pTail;
            paux->next = NULL;

            if (pTail != NULL) 
				pTail->next = paux;
            pTail = paux;
            if (pHead == NULL) 
				pHead = pTail;
        }

		 void addFront(int info, int ant) {
            struct Elem *paux;

            paux = new struct Elem;
            paux->value = info;
			paux->before = ant;
            paux->prev = NULL;
            paux->next = pHead;

            if (pHead != NULL) 
				pHead->prev = paux;
            pHead = paux;

            if (pTail==NULL) 
				pTail = pHead;
        }

		void removeFront() {
            struct Elem *paux;

            if (pHead != NULL) {
                paux = pHead->next;
                if (pHead == pTail) 
					pTail = NULL;
                delete pHead;
                pHead = paux;
                if (pHead != NULL) 
					pHead->prev = NULL;
            }
            else 
				fprintf(stderr, "Error - The deque is empty!\n"); 
		}

		void removeBack() {
            struct Elem *paux;

            if (pTail != NULL) {
                paux = pTail->prev;
                if (pHead == pTail) 
					pHead = NULL;
                delete pTail;
                pTail = paux;
                if (pTail != NULL) 
					pTail->next = NULL;
            }
            else 
				fprintf(stderr, "Error - The deque is empty!\n");
        }

		int isEmpty() {
            if(pHead == NULL)
				return 1;
			return 0;
        }
};

int main(){
	int i, K, N, x, r, n;
	long long S = 0;
	FILE *pf, *pg;
	
	pf = fopen("deque.in", "r");
	pg = fopen("deque.out", "w");

	fscanf(pf, "%d %d", &N, &K);
	class Deque D;

	n = 0; 
	for(i=1; i<=N; i++){
		fscanf(pf, "%d", &x);
		if(D.isEmpty()){
			D.addFront(x, 0);
			n++;
		}

		else
			if(D.pTail != NULL && D.pTail->value >= x){
				r = 0;
				while(D.pTail != NULL && D.pTail->value >= x){
					r = r + D.pTail->before + 1;
					D.removeBack();
				}
				D.addBack(x, r);
				n++;
			}
	
			else{
				D.addBack(x, 0);
				n++;
			}
		

		if(n == K){
			if(D.pHead != NULL && D.pHead->before == 0){
				S = S + D.pHead->value;
				D.removeFront();
			}

			else{
				D.pHead->before--;
				S = S + D.pHead->value;
			}
			n--;
		}

	}
	
	fprintf(pg, "%lld\n", S);

	fclose(pf);
	fclose(pg);

	return 0;
}