void main()
{
int se=1,zeros=0,c2=0,c5=0;
int num;
scanf("%d",&num);
for(int i=1;i<=num;i++)
int bb=i;
while(i%2==0)
c2++;
i=i/2;
}
while(i%5==0)
c5++;
i=i/5;
i=bb;
se=c2>c5? c5:c2;
printf("%d的階乘有%d個零\n",num,se);