YES

(format LCTRS :logic QF_LIA)
(fun f2 1 :sort (Int Int))
(fun u_15 2 :sort (Int Int Int))

(rule (u_15 n_0 w_4_1) w_4_1 :guard (< w_4_1 0) :vars ((n_0 Int) (w_4_1 Int)))
(rule (u_15 n_2 w_4_3) (+ n_2 w_4_3) :guard (>= w_4_3 0) :vars ((n_2 Int) (w_4_3 Int)))
(rule (f2 n_4) (u_15 n_4 (f2 (- n_4 1))) :guard (> n_4 1) :vars ((n_4 Int)))
(rule (f2 n_5) n_5 :guard (<= n_5 1) :vars ((n_5 Int)))

Confluent by Parallel Closedness with proof:
no critical pairs

Elapsed Time:  12.79 ms