Task: Program Execution
Input (English): ffbrLbPIfuSedcBGfFiinjwuSIIFCdTc, OUVJdHtLmxyRoGfFiinjwuSIIFCdvOckZYhCKr
Output (English): c, d, f, g, h, i, j, k, l, m, n, o, r, s, t, u, v, w, x, y, z