Arthur was always very afraid to meet girls. It's not even about Arthur's natural shyness, and not even so much about the fact that Arthur doesn't know what to talk about with girls. It’s just that Arthur hasn’t pronounced the letter “p” since childhood; and is very shy about it. Therefore, Arthur tries not to utter words once again that contain this hated letter.
One day, friends introduced Arthur to a girl named Nina (oh, what a beautiful name!). She was charming and very talkative, so Arthur hardly needed to find the words — she filled the awkward silence for him. Of course, he invited her to a cafe for a cup of coffee. Arthur even thought through all his lines in advance: "Happy to see you," "You're amazing today," "Yes, of course, I'm listening to you carefully," "What's next?", "The bill, please." and, of course, "I'll call you one of these days, don't be bored."
But, as you know, there are no ideal plans. Everything went like clockwork, but suddenly, sitting at a table in a cafe, Nina said that she had not slept terribly and would not refuse N cups of coffee. And then Arthur realized that he had not thought in advance how he would order. It's understandable to say something like, "How many cups of coffee, please?" Obviously you need to order at least N + 1 cup — so that Nina gets N cups, and drink it herself, but here's exactly how much — Arthur doesn't know. He doesn't have much money, so he doesn't want to order more than what is vital to avoid exposure.
Help Arthur — count how many cups of coffee he should order.
Input
One integer N is entered (1 ≤ N ≤ 2999).
Imprint
Print one number — the number of cups of coffee that Arthur should order.
Examples
| # |
Input |
Output |
| 1 |
1 |
2 |
| 2 |
12 |
15 |