## Goal

You have to correctly interpret `RPN` (Reverse Polish Notation) instructions and print the stack when the instruction line has been read (from left to right).

If the instruction is a number, simply put in on top of the stack (on the right).

The operations (`ADD`, `SUB`, `MUL`, `DIV`, `MOD`) pop the last two numbers out of the stack and push back on top the result. You can safely assume that the numbers are all integers.

For example after, `2 5 SUB 8`, the stack is `-3 8`.

`DIV` is the integer quotient and `MOD` the remainder of the division.

There are also operators that act on the stack itself:

`POP` removes the top number.

`DUP` duplicates the top number.

`SWP` swaps the two top numbers. `4 5 SWP 6` swaps 4 and 5 then pushes 6 on top, the stack is `5 4 6`.

`3 ROL` pops the top number (here itâ€™s 3) then brings to the top the third number of the stack. For example, if the stack is `1 2 3 4`, `3 ROL` changes it in `1 3 4 2`.
Input

The first line is the number of instructions on the second line.

The last line is the instructions line.

6

2 4 ADD 5 MUL -4

Output

You must print the stack, the top on the right.

If an instruction has fewer operands than needed or if we try to divide by 0, stop everything and print `ERROR` after the current stack. The popped values before the crash are still popped. For example if the stack is `1 2 3 0` and we try `MOD`, the stack will be `1 2` and you have to print `1 2 ERROR`.

30 -4