dim stack(5000, 3)	# BASIC-256 lacks functions (as of ver. 0.9.6.66)
stack[0,0] = 3		# M
stack[0,1] = 7		# N
lev = 0

gosub ackermann
print "A("+stack[0,0]+","+stack[0,1]+") = "+stack[0,2]
end

ackermann:
	if stack[lev,0]=0 then
		stack[lev,2] = stack[lev,1]+1
		return
	end if
	if stack[lev,1]=0 then
		lev = lev+1
		stack[lev,0] = stack[lev-1,0]-1
		stack[lev,1] = 1
		gosub ackermann
		stack[lev-1,2] = stack[lev,2]
		lev = lev-1
		return
	end if
	lev = lev+1
	stack[lev,0] = stack[lev-1,0]
	stack[lev,1] = stack[lev-1,1]-1
	gosub ackermann
	stack[lev,0] = stack[lev-1,0]-1
	stack[lev,1] = stack[lev,2]
	gosub ackermann
	stack[lev-1,2] = stack[lev,2]
	lev = lev-1
	return