View Compilation Error

342028_0_21477\Main.java:1: 需要 "class" 或 "interface"
var
^
342028_0_21477\Main.java:4: 需要 "class" 或 "interface"
begin
^
342028_0_21477\Main.java:9: 需要 "class" 或 "interface"
      s:=a+b;
      ^
342028_0_21477\Main.java:11: 需要 "class" 或 "interface"
      writeln(s);
      ^
342028_0_21477\Main.java:12: 需要 "class" 或 "interface"
      writeln
      ^
342028_0_21477\Main.java:15: 需要 "class" 或 "interface"
end.
^
6 错误