0 QTRS
fib(N) → sel(N, fib1(s(0), s(0))) fib1(X, Y) → cons(X, fib1(Y, add(X, Y))) add(0, X) → X add(s(X), Y) → s(add(X, Y)) sel(0, cons(X, XS)) → X sel(s(N), cons(X, XS)) → sel(N, XS)