#include <stdlib.h>
#include <stdio.h>


int fact0 ( int p)
{
  int x = 0;
  int i = 0;
while( i < p )
{
  x+=5;
  int incr = 0;
  int y = x;
  while( !(y%5) )
  {
    ++incr;
    y /= 5;
  }
  i += incr;
}

printf("%i",x);

}

int main()
{
 freopen("fact.in","r",stdin);
 freopen("fact.out","w",stdout);

 int p;
 scanf("%i",&p);
 fact0(p);

}