Add projecteuler solution for problem 20

[chamil321]

link: https://projecteuler.net/problem=20

n! means n × (n − 1) × ... × 3 × 2 × 1

For example, 10! = 10 × 9 × ... × 3 × 2 × 1 = 3628800,
and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27.

Find the sum of the digits in the number 100!

[pratik-2020]

please assign me this

[alokjai]

please assign me sir

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