-module(e2).
-export([e2/0, fib_count/4]).

fib_count(Last, Current, Max, Sum) when Current >= Max -> Sum;
fib_count(Last, Current, Max, Sum) when Current rem 2 == 0 -> fib_count(Current, Last + Current, Max, Sum + Current);
fib_count(Last, Current, Max, Sum) -> fib_count(Current, Last + Current, Max, Sum).

e2() -> fib_count(0, 1, 4000000, 0).