Pyramid

We write in the number of numbers from 1 to N (in the example N = 4).

1 2 3 4

Now under him write out the number of (N – 1) numbers, each of which is the product of two numbers that are above it:

1 2 3 4

2 6 12

Continue to prescribe the ranks, yet there will be a single number:

1 2 3 4

2 6 12

12 72

864

The result was an inverted pyramid on top of which number 864.

Input

In the first line of input data is the number of N (2 <= N <= 50).

Output

Remove the first digit of the bottom of the pyramid with the base of the N numbers.

Examples