#include<iostream>
#include<fstream>
using namespace std;

int main()
{
	ifstream inFile("fact.in");
	ofstream outFile("fact.out");

	int P;
	inFile >> P;

	unsigned int multiple_of_5 = 0, temp, counter_of_5 = 0;

	if (P == 0)
		outFile << 1;

	do
	{
		multiple_of_5 += 5;
		temp = multiple_of_5;
		while (temp % 5 == 0)
		{
			counter_of_5++;
			temp /= 5;
		}
	} while (counter_of_5 != P);

	outFile << multiple_of_5;
}