let e = 42
let t = 2017
gosub modularinverse
end
sub modularinverse
let d = 0
if e < t then
let b = e
let c = 1
do
let s = int(((t - b) / e) + 1)
let b = b + s * e
let c = c + s
let b = b - t
loop b <> 1
let d = c
endif
let m = d
print m
return