Task: Program Execution
Input (English): a t r 7799 r f 5317 d 9171 o 5677 x 1649 x x p 5353 i 3317 5551 q 583 7893 a u 6133 h z c z h 8091 d j z 3837 x j v q 5783 3027 h 2185 e
Output (English): a, c, d, e, f, h, i, j, o, p, q, r, t, u, v, x, z