Mimi and Christmas Cake

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Points: 5 (partial)
Time limit: 2.0s
Memory limit: 256M

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Problem type

For Christmas, Mimi got a fruit cake from her parents. The cake is sliced into N slices, and the i^{\text{th}} slice has f_i pieces of fruit on it. However, as Mimi is trying to lose weight as a New Year's resolution, she will only eat slices which have a prime number of fruits on them. Help Mimi determine how many slices of cake she can eat.

Constraints

Subtask 1 [10%]

1 \le N \le 100
1 \le f_i \le 100

Subtask 2 [10%]

1 \le N \le 10^5
1 \le f_i \le 1\,000

Subtask 3 [80%]

1 \le N \le 10^5
1 \le f_i \le 10^5

Input Specification

The first line of input will contain a single integer, N, the number of slices
The next and final line of input will contain N space-separated integers: f_1, f_2, \ldots, f_N, the number of pieces of fruit on the ith slice of cake.

Output Specification

A single integer, the number of slices of cake Mimi can eat.

Input Specification

3
1 5 8

Output Specification

1

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