Task: Program Execution
Input (English): 1543 x x 341 7421 i 5521 8933 k f 21 2619 d 579 7301 9731 m c i h 4467 v 269 l 5035 m 2651 g h f 2469 a t
Output (English): a, c, d, f, g, h, i, k, l, m, t, v, x