#include<stdio.h>
int v[15],t[15];
void genereaza(){
	v[1]=5;
	t[1]=6;
	v[2]=25;
	t[2]=31;
	v[3]=125;
	t[3]=156;
	v[4]=625;
	t[4]=781;
	v[5]=3125;
	t[5]=3906;
	v[6]=15625;
	t[6]=19531;
	v[7]=78125;
	t[7]=97656;
	v[8]=390625;
	t[8]=488281;
	v[9]=1953125;
	t[9]=2441406;
	v[10]=9765625;
	t[10]=12207031;
}
int main(){
	int s,i,p;
	genereaza();
	freopen("fact.in","r",stdin);
	freopen("fact.out","w",stdout);
	scanf("%d",&p);
	s=0;i=0;
	if (p==0){
		printf("1\n");
		return 0;
	}
	while (p>1){
		for (i=1;i<11&&t[i]<=p;++i);
		--i;
		s+=p/t[i]*v[i];
		p%=t[i];
	}
	/*
	while(s<p){
		i=i+5;
		s+=putere(i);
	}
	else 
		printf("%d\n",i);
	*/
	printf("%d\n",s);
	return 0;
}