def main():
    import sys
    input = sys.stdin.read
    data = input().split()
    N = int(data[0])
    K = int(data[1])
    A = list(map(int, data[2:2+N]))
    
    if N == 0:
        print(0)
        return
    
    # Compute for x = A[0]
    if K == 0:
        sum_T1 = 0
    else:
        m = min(K-1, N-1)
        sum_T1 = 0
        for i in range(1, 1 + m):
            sum_T1 += A[i] - A[0]
    
    sum_S1 = 0
    for i in range(N):
        sum_S1 += A[i] - A[0]
    F1 = 2 * sum_T1 - sum_S1
    
    # Compute for x = A[-1]
    if K == 0:
        sum_T2 = 0
    else:
        m = min(K-1, N-1)
        sum_T2 = 0
        start = max(0, (N-1) - m)
        for i in range(start, N-1):
            sum_T2 += A[-1] - A[i]
    
    sum_S2 = 0
    for i in range(N):
        sum_S2 += A[-1] - A[i]
    F2 = 2 * sum_T2 - sum_S2
    
    # The minimal value is the minimum of F1 and F2
    print(min(F1, F2))
    
if __name__ == '__main__':
    main()