Task: Program Execution
Input (English): 1, 4, ['1263', '6921', '3149', 'a', '505', '1735', 'q', '4041', '4427', '9375', '4063', 'X', 'R', 'Q', 'b', 'b', '1139', '6377', '4337', '1623', 'Z', '671', 'm', '6237', 'u', '4505', '5203', '3417', '1683', 'r']
Output (English): 126369213149a