import sys import ast def fun2(s): result = [] for i in range(len(s)): for j in range(i + 1, len(s)): # 判断两个字符串是否有重复字符 if len(set(s[i]) & set(s[j])) > 0: continue else: result.append(len(s[i]) * len(s[j])) return max(result) if result else 0 if __name__ == "__main__": for line in sys.stdin: s = line.strip() s = ast.literal_eval(s) print(fun2((s)))