#include <stdio.h>
int nr, x=5, y, p, c;
FILE *in, *out;
int main()
{
    in=fopen("fact.in","rt");
    out=fopen("fact.out","wt");
    fscanf(in, "%d", &p);
    if (p==0)
        fprintf(out, "1");
    else
    {
        while(nr<p)
        {
            y=x; c=0;
            while(y%5==0)
            {
                y=y/5;
                c++;
            }
            nr=nr+c;
            if(nr<p)
                x=x+5;
        }
        fprintf(out, "%d", x);
    }
    fclose(in);
    fclose(out);
    return 0;
}