#include<iostream.h>
#include<fstream.h>
main()
{
long int s,t,p,x,a[15000],b[15000],i,j,k,l,m,n,sp,aux,valid;
fstream f("fact.in",ios::in);
fstream g("fact.out",ios::out);
f>>p;
m=1000000;l=5;
if(p==0)g<<"1";
if(p==1)g<<"2";
else
{
 x=10;k=1;valid=0;sp=0;l=5;t=0;
 do{
    sp=x/5;
    if(sp==l){
	      t++;
	      l+=5;
	      }
    x+=5;
    }while((x<=(p*5))&&(x!=m));
 
 }
g<<x;
f.close();
g.close();
return 0;
}