WA #4，求调

#include<bits/stdc++.h>
using namespace std;
#define int long long
const int mod=1e9+7;
const int unmod=5e8+4;
int n,k;
signed main()
{
	cin>>k>>n;
    int sum=0;
    if(n==k) n--;
    if(n>k) sum+=(n-k)*k,n=k-1;
    sum%=mod;
    sum+=(n%mod)*(k%mod)%mod;
    int r;
    for(int i=1;i<=n;++i)
    {
    	int t=k/i;
    	if(t) r=min(n,k/t);
    	else  r=n;
    	sum-=(t%mod)*(((r%mod)-(i%mod)+1)%mod)*(((i%mod)+(r%mod))%mod)*(((mod+1)/2)%mod)/* *(unmod%mod)*/;
    	sum%=mod;
    	i=r;
    	//i=l
	}
	cout<<(sum+mod)%mod<<endl;
	return 0; 
}