https://ac.nowcoder.com/acm/problem/14682——约数的个数（计算贡献）

题目链接：https://ac.nowcoder.com/acm/problem/14682
思路：计算n以内每个数的贡献次数求和即可。
代码：

//#include<bits/stdc++.h>
#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<cmath>
#include<map>
#include<vector>
#include<set>
#include<utility>
#include<algorithm>
using namespace std;
typedef long long LL;
const int maxn=1e5+5;
const int N=1e8+5;
const LL mod=1e9+7;
int read() {
    char ch=getchar();int x=0,f=1;
    while(ch<'0' || ch>'9')    {if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0' && ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
int gcd_(int a,int b) {return b==0?a:gcd_(b,a%b);}
LL fpow(LL a,LL b) {
    LL res=1;
    while(b) {
        if(b&1) res=(res*a)%mod;
        a=(a*a)%mod;
        b>>=1;
    }
    return res;
}
int main() {
    //freopen("in.txt","r",stdin);
    //freopen("out.txt","w",stdout);
//    cout<<"Accepted!\n";
    int n;
    cin>>n;
    LL sum=0;
    for(int i=1;i<=n;++i) {
        sum+=n/i;    
    }
    cout<<sum;
    return 0;
}