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


int compare_desc(const void *a, const void *b) {
    return *(int*)b - *(int*)a;
}

int main() {
    int n, k;
    scanf("%d %d", &n, &k);
    
    int arr[5000];
    for (int i = 0; i < n; i++) 
        scanf("%d", &arr[i]);

    qsort(arr, n, sizeof(int), compare_desc);

    int sum = 0;
    
    for (int i = 0; i < k; i++) 
        sum += arr[i] - i;

    printf("%d", sum);
    return 0;
}