Pizza

Today is Sanggeun's birthday. He went out to eat pizza with his friends.

His friends are still young, so none of them can eat a whole pizza, but each friend knows exactly how much pizza they can eat.

Each friend's amount is always one of 1/4, 1/2, or 3/4 of a pizza.

Sanggeun will not eat any pizza himself. He wants every friend to receive exactly one slice whose size is the amount that friend can eat. Find the minimum number of whole pizzas he must order so that all friends can be satisfied.

The first line contains the number of friends N. (1 <= N <= 10,000)

Each of the next N lines contains the amount of pizza one friend can eat. Each value is one of 1/4, 1/2, or 3/4.

Print the minimum number of pizzas needed so that every friend can eat the amount they can eat.