# Write a python function to find the smallest missing number from the given array.
def find_First_Missing(array, start, end):
    if start > end:
        return end + 1
    if start != array[start]:
        return start
    mid = int((start + end) / 2)
    if array[mid] == mid:
        return find_First_Missing(array, mid + 1, end)
    return find_First_Missing(array, start, mid)
