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原题出处

image.png

#include <bits/stdc++.h>
using namespace std;
int main(){
    int n;
    scanf("%d",&n);
    int cnt=0;
    for(int i =5;i<=n;i+=5){
        //cout<<"I"<<i<<endl;
        int temp=i;
        while(temp%5==0){
            cnt++;
            //cout<<"t"<<cnt<<endl;
            temp/=5;
        }   
                
    }
    
    cout<<cnt;
    return 0;
}

#include <bits/stdc++.h>
using namespace std;
int main()
{
    int n, counter=0;
    cin >> n;
    while (n/=5)
    {
        counter += n;
    }
    cout << counter;
    return 0;
}