def main():
    """ Consider three-depth windows instead of individual depths:
        199  A      
        200  A B    
        208  A B C  
        210    B C D
        200  E   C D
        207  E F   D
        240  E F G  
        269    F G H
        260      G H
        263        H
        For each window in the list, determine whether it's deeper than the previous window.
        There is no previous depth for the first entry.
        Output the total number of times the depth increased.
    """
    with open("aoc1-1.txt", "r") as file:
        depths = file.readlines()
    depths = [int(el.strip()) for el in depths]
    prev = 999999999
    increases = []
    for i in range(len(depths)-2):
        window = depths[i] + depths[i+1] + depths[i+2]
        increases.append(1 if window > prev else 0)
        prev = window
    print(sum(increases))
            

if __name__ == "__main__":
    main()