CF989A A Blend of Springtime

**题目大意：** 给定一个由'A','B','C','.'构成的字符串，'A''B''C'控制左中右三个位置，问是否存在一个位置'A''B''C'同时控制

一个字符串

如果满足条件，输出"Yes"，否则输出"No" 感谢@守望 提供翻译

In the first example, the buff and canary yellow flowers can leave their petals in the central cell, blending all three colours in it. In the second example, it's impossible to satisfy the requirement because there is no way that amber and buff meet in any cell.