let rec aux_simple = 
  ((i: int)): int => 
    if(i
    < 100) {
      aux_simple(i + 1)
    } else {
      i
    };

let counter_simple = ((n: int)): int => aux_simple(n);

type sum_aggregator = {counter: int, sum: int };

let counter = 
  ((n: int)): int => 
    {
      let initial: sum_aggregator = {counter: 0, sum: 0 };
      let rec aggregate = 
        ((prev: sum_aggregator)): int => 
          if(prev.counter
          <= n) {
          
            
            aggregate({
                counter: prev.counter + 1,
                sum: prev.counter + prev.sum
              })
          } else {
            prev.sum
          };
      aggregate(initial)
    };

let rec aux_nest = 
  ((prev: sum_aggregator)): sum_aggregator => 
    if(prev.counter
    < 100) {
    
      let sum: int = prev.sum + aux_simple(prev.counter);
      aux_nest({counter: prev.counter + 1, sum: sum })
    } else {
      ({counter: prev.counter, sum: prev.sum })
    };

let counter_nest = 
  ((n: int)): int => 
    {
      let initial: sum_aggregator = {counter: 0, sum: 0 };
      let out: sum_aggregator = aux_nest(initial);
      out.sum
    };