// O( min( N , M ) )の愚直解チェック
#include<bits/stdc++.h>
using namespace std;

using ll = long long;

#define TYPE_OF( VAR ) remove_const<remove_reference<decltype( VAR )>::type >::type
#define UNTIE ios_base::sync_with_stdio( false ); cin.tie( nullptr ) 
#define CIN( LL , A ) LL A; cin >> A 
#define ASSERT( A , MIN , MAX ) assert( MIN <= A && A <= MAX ) 
#define CIN_ASSERT( A , MIN , MAX ) CIN( TYPE_OF( MAX ) , A ); ASSERT( A , MIN , MAX ) 
#define FOREQ( VAR , INITIAL , FINAL ) for( TYPE_OF( FINAL ) VAR = INITIAL ; VAR <= FINAL ; VAR ++ )  
#define QUIT return 0 
#define RETURN( ANSWER ) cout << ( ANSWER ) << "\n"; QUIT 

int main()
{
  UNTIE;
  constexpr const ll bound = 1000000000;
  CIN_ASSERT( N , 1 , bound );
  CIN_ASSERT( M , 1 , bound );
  // sum( ll i = 1 ; i <= N ; i++ ) sum( ll j = 1 ; j <= M ; j++ ){ i % j }
  // = sum( ll j = 1 ; j <= M ; j++ ) sum( ll i = 1 ; i <= N ; i++ ){ i % j }
  // = sum( ll j = 1 ; j <= M ; j++ ){ ( N / j ) * ( ( j - 1 ) * j ) / 2 + ( N % j ) * ( N % j + 1 ) / 2 }
  constexpr const ll P = 998244353;
  ll answer0 = 0;
  ll answer1 = 0;
  ll N_r;
  ll j_sum = 0;
  FOREQ( j , 1 , M ){
    N_r = N % j;
    j_sum = ( j_sum + j - 1 ) % P;
    answer0 += ( ( N / j ) * j_sum ) % P;
    answer1 += ( N_r * ( N_r + 1 ) ) % P;
  }
  answer1 = ( answer1 % P ) * ( ( P + 1 ) / 2 );
  RETURN( ( answer0 + answer1 ) % P );
}