#include <stdio.h>

int main()
{
	long int p, k = 0, v = 0;
	long long k1 = 0,k2 = 0,i= 1, j =1;
	int x = 1, flag = 0;
	FILE *in, *out;
	in = fopen("fact.in","r");
	fscanf(in,"%ld",&p);
	fclose(in);
	out = fopen("fact.out","w");
	if(p==0)fprintf(out,"%ld",x);
	else 
	{
		while(k < p)
		{
			i = j;
			i = i*5;
			v = i;
			j++;
			if((i*5)%10 != 0) k1++;
			flag = 0;
			while(flag == 0)
			{
				if((i)%10 == 0)
				{
					i = i/10;
					flag = 0;
					k2++;
				}else flag = 1;
			}
			k = k1+k2;
		
		}
		fprintf(out,"%ld",v);
	}
	fclose(out);
	return 0;
}