BZOJ 1968

#include<cstdio>
#include<algorithm>
#include<cmath>
#define N 200010
#define rg register
#define ll long long
using namespace std;
int n,m;
void read(int &k){
    k=0; int f=1; char c=getchar();
    while(c<‘0‘||c>‘9‘)c==‘-‘&&(f=-1),c=getchar();
    while(‘0‘<=c&&c<=‘9‘)k=k*10+c-‘0‘,c=getchar();
    k*=f;
}
int main(){
    read(n); ll ans=0;
    for(rg int i=1;i<=n;i++) ans+=n/i;
    printf("%lld\n",ans);
    return 0;
}