#include<stdio.h>

long long P;
long long N;
long long nr = 0;

int main()
{
	FILE *g = fopen("fact.out","w");
	FILE *f = fopen("fact.in","r");
	
	fscanf(f,"%llu",&P);
	if(!P)
		fprintf(f,"1");
	else
	{
		for(N=5;nr<P;N+=5)
		{
			long long i = N;
			while(i%5 == 0)
			{
				i /= 5;
				nr ++;
			}
		}
		if(nr == P)
			fprintf(g,"%llu",N-5);
		else
			fprintf(g,"-1");
	}
	
	fclose(g);
	fclose(f);
	return 0;
}