CF44A Indian Summer

Indian summer is such a beautiful time of the year! A girl named Alyona is walking in the forest and picking a bouquet from fallen leaves. Alyona is very choosy — she doesn't take a leaf if it matches the color and the species of the tree of one of the leaves she already has. Find out how many leaves Alyona has picked.

The first line contains an integer $ n $ ( $ 1

Output the single number — the number of Alyona's leaves.