コンパイルエラー

./Main.cpp: In function 'int main()':
./Main.cpp:4:13: error: 'cin' was not declared in this scope
    4 |   int A, B; cin >> A >> B;
      |             ^~~
./Main.cpp:1:1: note: 'std::cin' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
  +++ |+#include <iostream>
    1 | using namespace std;
./Main.cpp:5:3: error: 'cout' was not declared in this scope
    5 |   cout << A + B << endl;
      |   ^~~~
./Main.cpp:5:3: note: 'std::cout' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
./Main.cpp:5:20: error: 'endl' was not declared in this scope
    5 |   cout << A + B << endl;
      |                    ^~~~
./Main.cpp:1:1: note: 'std::endl' is defined in header '<ostream>'; did you forget to '#include <ostream>'?
  +++ |+#include <ostream>
    1 | using namespace std;