Score : 200 points
Takahashi is practicing shiritori alone again today.
Shiritori is a game as follows:
In this game, he is practicing to announce as many words as possible in ten seconds.
You are given the number of words Takahashi announced, N, and the i-th word he announced, W_i, for each i. Determine if the rules of shiritori was observed, that is, every word announced by him satisfied the conditions.
Input is given from Standard Input in the following format:
N W_1 W_2 : W_N
If every word announced by Takahashi satisfied the conditions, print Yes
; otherwise, print No
.
4 hoge english hoge enigma
No
As hoge
is announced multiple times, the rules of shiritori was not observed.
9 basic c cpp php python nadesico ocaml lua assembly
Yes
8 a aa aaa aaaa aaaaa aaaaaa aaa aaaaaaa
No
3 abc arc agc
No