Task: Program Execution
Input (English): G, Z, f, u, D
Output (English): [['G', 'Z', 'f', 'u'], ['G', 'Z', 'f', 'D'], ['G', 'Z', 'u', 'D'], ['G', 'f', 'u', 'D'], ['Z', 'f', 'u', 'D']]