static boolean valid ( int r , int c ) {
  return r >= 0 && r < n && c >= 0 && c < m ;
}

static boolean valid ( int r , int c ) { return r >= 0 && r < n && c >= 0 && c < m ; }
(method_declaration (modifiers) type: (boolean_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier)) (formal_parameter type: (integral_type) name: (identifier))) body: (block (return_statement (binary_expression left: (binary_expression left: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (binary_expression left: (identifier) right: (identifier))) right: (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (binary_expression left: (identifier) right: (identifier))))))