require 'openssl'

def modinv(a, m)
  m0, inv, x0 = m, 1, 0
  while a > 1
    inv -= (a / m) * x0
    a, m = m, a % m
    inv, x0 = x0, inv
  end
  inv += m0 if inv < 0
  inv
end

x0 = 171988490999968958074461906163126253991
x1 = 149759767375550138601832127658924300851
x2 = 21392649857558566532141954695914673807
x3 = 52236160143411890255640980579270361316
x4 = 22081153611165744867415455406756477578

r0 = x1 - x0
r1 = x2 - x1
r2 = x3 - x2
r3 = x4 - x3

m1 = r0 * r3 - r1 * r2
m2 = r0 * r2 - r1 * r1

puts(m1.gcd(m2))

m = 176112297761995517109581492781981180247
x = x0
a = r1 * modinv(r0 % m, m) % m
b = (x1 - a * x) % m

puts(x1)
puts((a * x + b) % m)
puts(x2)
puts((a * x1 + b) % m)
puts(x3)
puts((a * x2 + b) % m)

x5 = (a * x4 + b) % m

puts("x5 = #{x5}")