print multInv(42, 2017)
end
function multInv(a,b)
b0 = b
multInv = 1
if b = 1 then goto [endFun]
while a > 1
q = a / b
t = b
b = a mod b
a = t
t = x0
x0 = multInv - q * x0
multInv = int(t)
wend
if multInv < 0 then multInv = multInv + b0
[endFun]
end function