List iota(int n) {
  List ret = new MTList : List();
  while(n > 0) {
    ret = new ConsList : List(car = new Int : IInt(value = n), cdr = ret);
    n = n - 1;
  };
  return ret;
}

int main() {
  List x = iota(100);
  List y = x.map(fun(Any x) {
                   if(x isa IInt) {
                     new Int : IInt(value = (x : IInt).value * 2);
                   } else {
                     x;
                   };
                 });
  (y.foldl(fun(Any x, Any i) {
             if x isa IInt && i isa IInt {
               new Int : IInt(value = (x : IInt).value + (i : IInt).value);
             } else { i; } ; 
           }, new Int : IInt(value = 0)) : IInt).value;
}