#include<stdio.h>
//#include<conio.h>

int main()
{
//clrscr();
int p,n,i,j,x,r,c,k,v5[14],v6[14]={0};
freopen("fact.in","r",stdin);
freopen("fact.out","w",stdout);
scanf("%d",&p);
v5[0]=1;
for(i=1;i<14;i++)v5[i]=v5[i-1]*5;
v6[0]=1;
for(i=1;i<14;i++)
	for(j=0;j<=i;j++)
		v6[i]+=v5[j];
	x=p;
	n=0;
	while(x)
			{
			j=0;
			while(x>=v6[j])j++;
			j--;
			x=x-v6[j];
			n=n+v5[j+1];
			}
	printf("%d",n);

return 0;
}