Language: C++

#include<bits/stdc++.h>
#include<algorithm>
#include<math.h>
#include<iostream>
using namespace std;
long long int lcm(long long int a,long long int b){
  long long int n;
  n=a*b/__gcd(a,b);
  return n;
}
using ll =long long int;
#define ci(a) cin>>a
#define co(a) cout<<a<<endl
#define gcd(a,b) __gcd(a,b)
#define vec vector<ll>
#define For(i,a,b) for(ll i=a;i<b;i++)
#define rFor(i,a,b) for(ll i=a;i>b;i--)
#define wFor(i,a,b) for(ll i=a;i<b;i+=2)
#define wrFor(i,a,b) for(ll i=a;i>b;i-=2)
#define sort(a,b) sort(a.begin(),b.end())
#define reverse(a,b) reverse(a.begin(),b.end())
//gcd 最大公約数
//lcm 最小公倍数
//double 少数（変数）
//string 文字列（変数）
//sqrt 平方根
//ceil 天井関数
//floor 床関数
//abs 絶対値
//pow 累乗
//cbrt  立方根
//hypot 平方和の平方根
//(string-'0') 文字列を数字に変換
//(char-'0') 数字に変換
//vector<vector<int>> data(a,vector<int>(b)) a×b行列
//for(int i=0;i<a;i++)
//for(int j=0;j<b;j++)
//cin>>data.at(i).at(j)  a×b行列の入力
//floor(log10(a)+1) aの10進法での桁数
//ceil(log10(a)) aの10進法での桁数

int main() {
  ll a,b;
  ci(a>>b);
  co(max(a-b,0));
}

Compiler output:
a.cc: In function 'int main()':
a.cc:45:9: error: no matching function for call to 'max(ll, int)'
   45 |   co(max(a-b,0));
      |      ~~~^~~~~~~
a.cc:13:21: note: in definition of macro 'co'
   13 | #define co(a) cout<<a<<endl
      |                     ^
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:45:9: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'int')
   45 |   co(max(a-b,0));
      |      ~~~^~~~~~~
a.cc:13:21: note: in definition of macro 'co'
   13 | #define co(a) cout<<a<<endl
      |                     ^
/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:45:9: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   45 |   co(max(a-b,0));
      |      ~~~^~~~~~~
a.cc:13:21: note: in definition of macro 'co'
   13 | #define co(a) cout<<a<<endl
      |                     ^