foo.cc:1:1: error: ‘import’ does not name a type
    1 | import java.math.BigInteger;
      | ^~~~~~
foo.cc:1:1: note: C++20 ‘import’ only available with ‘-fmodules-ts’
foo.cc:2:1: error: ‘import’ does not name a type
    2 | import java.util.ArrayList;
      | ^~~~~~
foo.cc:2:1: note: C++20 ‘import’ only available with ‘-fmodules-ts’
foo.cc:3:1: error: ‘import’ does not name a type
    3 | import java.util.List;
      | ^~~~~~
foo.cc:3:1: note: C++20 ‘import’ only available with ‘-fmodules-ts’
foo.cc:4:1: error: ‘import’ does not name a type
    4 | import java.util.Scanner;
      | ^~~~~~
foo.cc:4:1: note: C++20 ‘import’ only available with ‘-fmodules-ts’
foo.cc:6:1: error: expected unqualified-id before ‘public’
    6 | public class Main {
      | ^~~~~~