The school organizes students majoring in computer science to visit Qixia Mountain and uses school buses to take them to.But the school bus is limited to only one, so we need to rent a bus outside the school to take our students there. Assuming that the passenger capacity of the rented car is the same as that of the school bus, both are 50; May I ask how many buses need to be rented at least to take all students to Qixia Mountain (on a class basis, students in one class must be in the same bus, and one bus can carry multiple classes, with a maximum of 50 students in each class).

There are a total of 2 lines of input.
The first line is a positive integer n, representing the number of classes.
The second line has n positive integers, representing the number of people class Ci, separated by spaces.

Output the minimum number of vehicles that need to be rented.

1 ≤ n ≤ 100

1 ≤ Ci ≤ 50