Task: Program Execution
Input (English): 11, 21, ['Y', 't', 'E', 'f', 'f', '349', 'y', '9137', '3139', '2223', '1609', 'C', '2717', 'b', '677', 't', '9693', 'W', '1587', 'r', 'U']
Output (English): 1609C2717b677t9693W1587rU