[
 (program) {
  (namespace_definition) {
   (namespace_header) {
    namespace
    A
   }
   (namespace_body) {
    {
    (namespace_declarations_list) {
     (namespace_definition) {
      (namespace_header) {
       namespace
       B
      }
      (namespace_body) {
       {
       (namespace_declarations_list) {
        (namespace_definition) {
         (namespace_header) {
          namespace
          C
         }
         (namespace_body) {
          {
          (namespace_declarations_list) {
           (function_definition) {
            (decl_specifiers) {
             (builtintype) {
              void
             }
            }
            (lvalue) {
             main
            }
            (formal_args_list) {
             (
             )
            }
            (function_body) {
             {
             (stmt_list) {
              (return_statement) {
               return
               ;
              }
             }
             }
            }
           }
           (variable_declaration) {
            (decl_specifiers) {
             (builtintype) {
              int
             }
            }
            (definition_list) {
             (lvalue) {
              r
             }
            }
            ;
           }
          }
          }
         }
        }
       }
       }
      }
     }
    }
    }
   }
  }
  (variable_declaration) {
   (decl_specifiers) {
    (builtintype) {
     int
    }
   }
   (definition_list) {
    (lvalue) {
     m
    }
   }
   ;
  }
  (variable_declaration) {
   (decl_specifiers) {
    (builtintype) {
     int
    }
   }
   (definition_list) {
    (lvalue) {
     o
    }
   }
   ;
  }
 }
]