Even rain

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문제

There are nn columns of width 11 touching by sides arranged from left to right. Column that is ii-th from the left has height h_ih\_i.

When the rain falls, water can get stuck in some places. It happens when there are short columns between two high columns.

Formally, water will remain in every point which is neither an interior nor boundary of a column, but for which there exist points on the same height belonging to some columns both on the left and on the right. 

We are interested in an area of stuck water. If heights h_ih\_i are all integers, this area is an integer as well. Superstition of elderly foretells that happiness is brought when the area of stuck water is divisible by 22.

It seems it will be raining today. However, before that you plan to remove kk columns, i.e. change their heights to 00. How many out of (nk)n \choose k possibilities of removing columns will result in area of stuck water being even? Print the result modulo 109+710^9+7.

입력

First line of input contains two integers nn and kk (1n25,0001 \leq n \leq 25\\,000, 0kmin(25,n1)0 \leq k \leq \min(25, n - 1)), denoting number of columns and number of columns to be removed.

Second line of input contains nn integers h_1,,h_nh\_1, \ldots, h\_n (1h_i1091 \leq h\_i \leq 10^9) --- heights of columns from left to right.

출력

You need to print one number --- number of possibilities modulo 109+710^9+7 to remove kk columns so that area of stuck water will be even.

힌트

Explanation of first sample test:

Big picture on the left depicts initial setting of columns. Smaller pictures depict each of 77 possibilities of removing one column (pointed by an arrow). Grey areas depict stuck water.

In 44 cases area of stuck water (number next to each picture) is even.