Cities
When playing the cities game each player has to name a city, and the next player has to name a city that starts with the last letter of the city that was just named. So, if someone said Moscow
, the next player can say Warsaw
as Moscow
ends with w
.
Given a game where each new city is separated from the previous one with a comma and a space, your task is to find out if it’s a valid game. Otherwise, you should tell that someone has already lost.
The input contains a single line where each named city is separated by a ', '
from the previous one.
The program should output Go on
if the game is valid so far, and Stop!
if someone messed up in the chain of cities.
Input | Output |
---|---|
Moscow, Warsaw, West Jordan, Nashville | Go on |
Warsaw, Moscow | Stop! |
Moscow, Amsterdam | Stop! |
Constraints
Time limit: 2 seconds
Memory limit: 512 MB
Output limit: 1 MB