The epidemiologist W. Andy wants to find the index case of an ongoing crisis. To do this, he modelled the city of the outbreak and its $$$n$$$ residents with a cellular automaton. The city is represented by $$$n$$$ cells numbered from $$$1$$$ to $$$n$$$ and each cell has two neighbouring cells, one to its left and one to its right. The left neighbour of cell $$$i$$$ is cell $$$i-1$$$ and the right neighbour is cell $$$i+1$$$. Additionally, the left neighbour of cell $$$1$$$ is cell $$$n$$$ and the right neighbour of cell $$$n$$$ is cell $$$1$$$. Thus, the city and the corresponding automaton form a simple cycle.
Each cell contains an integer between $$$1$$$ and $$$m$$$ which represents how likely it is that this person is infected. Since the virus can only be transmitted by personal contact, the value in the $$$i$$$th cell on day $$$d$$$ only depends on the values of its neighbours and itself on the previous day. If we denote this value by $$$s_{d}[i]$$$, then the outbreak can be simulated by a function $$$f$$$ using the formula: $$$s_{d}[i]=f\big(s_{d-1}[i-1],s_{d-1}[i],s_{d-1}[i+1]\big).$$$ Note that as the city is cyclic both $$$i+1$$$ and $$$i-1$$$ are calculated modulo $$$n$$$.
Andy wants to find the index case, so he first has to find $$$s_0$$$, the state of the city on day zero. This poses a problem, however, as it is not known on which day the crisis started. Right now, Andy believes that he accomplished the task and found the state $$$s_0$$$, but you are not convinced. Therefore, you want to check if there may be a state previous to the initial state proposed by Andy, i.e. whether there exists any state $$$s_{-1}$$$ that gets transformed into $$$s_0$$$ by applying $$$f$$$.
The input consists of:
Output yes if there exists at least one possible previous state and no otherwise.
4 2121221211 2 1 2
YES
6 2121221211 2 1 2 1 2
NO
10 2121122221 2 2 2 1 2 1 2 1 2
YES
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