3443.Prime Number

Time Limit: 1s Memory Limit: 256MB

Simon has a prime number x and an array of non-negative integers a1,a2,...,an.Simon loves fractions very much. Today he wrote out number 3443_1.png on a piece of paper. After Simon led all fractions to a common denominator and summed them up, he got a fraction: 3443_2.png, where number t equals xa1+a2+...+an. Now Simon wants to reduce the resulting fraction. Help him, find the greatest common divisor of numbers s and t. As GCD can be rather large, print it as a remainder after dividing it by number 1000000007 (109+7).

Input Format(From the terminal/stdin)

Input The first line contains two positive integers n and x (1 \le n \le 105, 2 \le x \le 109) - the size of the array and the prime number.The second line contains n space-separated integers a1,a2,...,an (0 \le a1 \le a2 \le ... \le an \le 109).

Output Format(To the terminal/stdout)

Output Print a single number - the answer to the problem modulo 1000000007 (109+7).

Sample Input 1

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2 2
2 2
 · \n
 · \n

Sample Output 1

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8
 \n

Sample Input 2

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3 3
1 2 3
 · \n
 · · \n

Sample Output 2

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27
  \n

Sample Input 3

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2 2
29 29
 · \n
  ·  \n

Sample Output 3

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73741817
        \n

Sample Input 4

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4 5
0 0 0 0
 · \n
 · · · \n

Sample Output 4

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1
 \n

Hints

In the first sample 3443_3.png. Thus, the answer to the problem is 8.In the second sample, 3443_4.png. The answer to the problem is 27, as 351=13 \cdot 27, 729=27 \cdot 27.In the third sample the answer to the problem is 1073741824mod1000000007=73741817.In the fourth sample 3443_5.png. Thus, the answer to the problem is 1.

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