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UPEEC

Factorial

Easy#basics#loops#math· solved by 0 · time limit 2.0 s

Print n!=1×2×⋯×nn! = 1 \times 2 \times \dots \times n. By definition 0!=10! = 1.

Input

A single integer nn.

Output

n!n!

Constraints

0≤n≤200 \le n \le 20 (fits in a 64-bit integer).

Sample 1

Input

5

Output

120

Sample 2

Input

0

Output

1

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