#include<stdio.h>
using namespace std;
int s;long int p,x,cx;
int main()
{
FILE*f=fopen("fact.in","r");
FILE*g=fopen("fact.out","w");
fscanf(f,"%d",&p);
if(p==0)fprintf(g,"1");
else {while(p>0)
     {  x+=5;cx=x;
        while(cx%5==0)
        {p--;cx/=5;}
     }
    if(p==0)fprintf(g,"%d",x);}
    fclose(f);
    fclose(g);
    return 0;
}