Language: C++

#include<bits/stdc++.h>
using namespace std;
#define all(x) (x).begin(),(x).end()
typedef long long ll;
#define rep(i,n) for(ll i=0, i##_len=(n); i<i##_len; ++i)
#define REP(i,num,n) for(ll i=num, i##_len=(n); i<i##_len; ++i)
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
const ll LLINF = 1LL<<60;
const int INTINF = 1<<30;
const int MOD = 1000000007;

void add(long long &a, long long b) {
  a += b;
  if (a >= MOD) a -= MOD;
}

const int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
const int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};


int main(void){
    cin.tie(0);
    ios::sync_with_stdio(false);
    ll N,K;
    cin >> N >> K;
    ll ans = 0;
    REP(b, 1, N+1){
      ans += max(0, b - k) * (N/b) + max(0, N % b - K + 1);
    }
    if(K == 0) ans = N * N;
    cout << ans << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:31:25: error: 'k' was not declared in this scope
   31 |       ans += max(0, b - k) * (N/b) + max(0, N % b - K + 1);
      |                         ^
a.cc:31:41: error: no matching function for call to 'max(int, ll)'
   31 |       ans += max(0, b - k) * (N/b) + max(0, N % b - K + 1);
      |                                      ~~~^~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:31:41: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'll' {aka 'long long int'})
   31 |       ans += max(0, b - k) * (N/b) + max(0, N % b - K + 1);
      |                                      ~~~^~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:31:41: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   31 |       ans += max(0, b - k) * (N/b) + max(0, N % b - K + 1);
      |                                      ~~~^~~~~~~~~~~~~~~~~~