#include <stdio.h>
#include <malloc.h>
//计算1000!尾数零的个数
//扩展n!的尾数零的个数
//2^a * 5^b
//obviously a>b
//so count = b
//5*1 5*2 .....5*200 200个 除以5
//1 2 3 4 5 .... 200 中 包含 5*(1,2,3,4,...40) 40个 除以5
//5*1 5*2 ..... 5*8 void calc1(int n){
int count=;
int i=,t;
for(;i<=n;i++)
{
t = i;
while(t%==)
{
count++;
t = t/;
}
}
printf("%d",count);
} void calc2(int n)
{
int sum=;
while(n)
{
n/=;
sum+=n;
}
printf("%d",sum);
} int main () {
int n = ;
calc2(n);
return ;
}