input = [[1,2],[2,3],[4,1],[4,1],[2,1],[4,6],[2,1],[1,2]]
def partition(arr,low,high):
    i = ( low-1 )         # index of smaller element
    pivot = val(arr[high])     # pivot
    for j in range(low , high):
        # If current element is smaller than or
        # equal to pivot
        if   val(arr[j]) <= pivot:
            # increment index of smaller element
            i = i+1
            arr[i],arr[j] = arr[j],arr[i]
    arr[i+1],arr[high] = arr[high],arr[i+1]
    return ( i+1 )
def val(inslist):
    return (inslist[0]*10+inslist[1])
def quickSort(arr,low,high):
    if low < high:
        pi = partition(arr,low,high)
        quickSort(arr, low, pi-1)
        quickSort(arr, pi+1, high)
arr = input
n = len(arr)
quickSort(arr,0,n-1)
print ("Sorted array is:")
print(arr)