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

ifstream in("fact.in");
ofstream out("fact.out");

long i,s,n;
vector<long> x;
vector<long> sume;

void breakdiv2(long x)
{
while(!(x%5))
	{s--;x/=5;}
}

void breakdiv(long x)
{
while(!(x%5))
	{s++;x/=5;}
}

int main()
{
in>>n;
if(!n)
	{
	out<<1;
	return 0;
	}
else
	{
	for(i=25; s<n; i+=25)
		{breakdiv(i);s+=4;}i-=25;
	while(s>n)
		{breakdiv2(i);i-=5;}
	if(s<n)
		s++;
	out<<i;
	}
	
return 0;
}