#include<stdio.h>
FILE *in,*out;
int nr5=1,p;
int num=5,aux;
int main()
{
	in=fopen("fact.in","rt");
	out=fopen("fact.out","wt");
	fscanf(in,"%d",&p);
	
	if(p>0)
	{
		while(nr5<p)
		{
			num+=5;
			aux=num;
			while(aux%25==0)
			{
				nr5+=2;
				aux/=25;
			}
			while(aux%5==0)
			{
				nr5++;
				aux/=5;
			}
		}
		if(nr5==p)
			fprintf(out,"%d",num);
		else
			fprintf(out,"-1");
	}
	else
		fprintf(out,"1");
		
	return 0;
}