#This problem was asked by Stripe

#Given an array of integers, find the first missing positive integer
#in linear time and constant space. In other words, find the lowest 
#positive integer that does not exist in the array. The array can
#contain duplicates and negative numbers as well.

#For example, the input[3, 4, -1, 1] should give 2. The input [1, 2, 0]
#give 3.

#You can modify the input array in-place
def function():
    


