This project was created after I saw meme.
Standard deviation method is not optimal. Example:
ATM Status:
100$ - 3
50$ - 3
20$ - 2
5$ - 2
Total sum - 500
Enter requested amount of money: 400
ATM Status:
100$ - 1
50$ - 0
20$ - 0
5$ - 0
Total sum - 100
Decision to dispense all money except 1x 100$ is not good as ATM cannot dispense any other amount of money now.