// 2 Stacks

PUSH 0 1 // Counter 1-1000
PUSH 1 0 // Total

JMP start

:sumIfMultiple

PUSH 1 s0
PUSH 1 3
MOD 1
JZ 1 add

POP 1
PUSH 1 s0
PUSH 1 5
MOD 1
JZ 1 add
POP 1
RET

:add
POP 1
PUSH 1 s0
ADD 1

RET

:start
CALL sumIfMultiple
PUSH 0 1
ADD 0
PUSH 0 s0
PUSH 0 1000
SUB 0
JZ 0 end
POP 0
JMP start

:end
WRITE s1