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Factorial of N
Easy
4 solved
Factorial of N
The factorial of N, written N!, is the product of every integer from 1 to N. For example 4! = 4 3 2 * 1 = 24.
By definition 0! is 1.
Given N, print N!. The answer grows very fast, so in C, C++ or Java use a 64-bit type (long long / long). Python handles big integers on its own.
Input
A single line containing one integer N.
Output
A single integer: the value of N!.
Constraints
0 <= N <= 20
Example 1
Input
5
Output
120
5 * 4 * 3 * 2 * 1 = 120
Submit runs your code against 5 test cases — the 1 shown above plus 4 hidden ones covering the awkward cases. Run sample just tries the first example, which is usually what you want while you are still working it out.