def bsort (A):
    h,t,n = 0,0,len(A)
    while h == 0:
        h = 1 
        for i in range(n-t-1):
            if A[i] > A[i+1]:
                h = 0
                A[i] , A[i+1] = A[i+1] , A[i]
        t += 1
    return(A)

def BS(A,k,s=0,l=0,h='none'):
    if s == 1:
        A = bsort(A) 
    if h == 'none':
        h = len(A)-1 
        
    if h < l: 
        return None
    else:
        m = l + (h-l)//2  

    if A[m] > k:
        return BS(A,k,0,l,m-1)
    elif A[m] < k:
        return BS(A,k,0,m+1,h)
    else:
        return m