CF158B Taxi

After the lessons $ n $ groups of schoolchildren went outside and decided to visit Polycarpus to celebrate his birthday. We know that the $ i $ -th group consists of $ s_{i} $ friends ( $ 1

The first line contains integer $ n $ ( $ 1

Print the single number — the minimum number of taxis necessary to drive all children to Polycarpus.

In the first test we can sort the children into four cars like this: - the third group (consisting of four children), - the fourth group (consisting of three children), - the fifth group (consisting of three children), - the first and the second group (consisting of one and two children, correspondingly). There are other ways to sort the groups into four cars.