#include <stdio.h>

long p,n,t;
int main()
{
    FILE*f,*g;
    f=fopen("fact.in","r");
    g=fopen("fact.out","w");
    fscanf(f, "%ld", &p);

    if(p==0) fprintf(g, "1");
        else
        {
            while(p!=0)
            {
                n+=5;
                if(n%25==0)
            {
                t=n;
                t/=25;
                p-=2;
                while(t%5==0)
                {
                    p--;
                    t/=5;
                }
            }
            else p--;
        }
    if(p<0) fprintf(g,"-1");
        else fprintf(g,"%ld", n);

    fclose(f);
    fclose(g);
    return 0;
            }
}