text: 
  const { I, M, K, KI, C, B } = require('./combinators');
  
  // \afb.f (n f a)
  const succ = n => f => a => B(f)(n(f))(a);
  
  const _0 = KI;
  const _1 = succ(_0);
  const _2 = succ(_1);
  const _3 = succ(_2);
  const _4 = succ(_3);
  const _5 = succ(_4);
  
  // \ab.a succ b
  const add = a => b => a(succ)(b);
  
  // add _1
  const increment = add(_1); // Or succ
  
  // \ab.a (add b) _0 == \abf.a (b f) == B
  const mul = B;
  
  // \ab.ab
  const pow = a => b => b(a);
  
  module.exports = {
    _0, _1, _2, _3, _4, _5,
    add, mul, increment, pow,
  };
  
  