#D8696. Xor Array

    ID: 7230 Type: Default 2000ms 268MiB

Xor Array

Xor Array

Problem statement

Given the integers N N and X X . Find the remainder by dividing the number of sequences of length N N that satisfy the following conditions by 998244353 998244353 .

  • The sequence is a monotonous increase in a broad sense.
  • Each element of the sequence is greater than or equal to 0 0 and less than or equal to X X .
  • The exclusive OR (xor) of all elements is X X .

Constraint

  • 1 leqN leq500 1 \ leq N \ leq 500
  • 0 leqX leq500 0 \ leq X \ leq 500
  • N N and X X are integers.

input

Input is given from standard input in the following format.

N N X X

output

Output the answer.


Input example 1

twenty three

Output example 1

2

The sequences 0,3 \\ {0,3 \\} and 1,2 \\ {1,2 \\} satisfy the condition.


Input example 2

1 1

Output example 2

1

Only the sequence 1 \\ {1 \\} meets the condition.


Input example 3

224 239

Output example 3

400351036

Example

Input

2 3

Output

2

inputFormat

input

Input is given from standard input in the following format.

N N X X

outputFormat

output

Output the answer.


Input example 1

twenty three

Output example 1

2

The sequences 0,3 \\ {0,3 \\} and 1,2 \\ {1,2 \\} satisfy the condition.


Input example 2

1 1

Output example 2

1

Only the sequence 1 \\ {1 \\} meets the condition.


Input example 3

224 239

Output example 3

400351036

Example

Input

2 3

Output

2

样例

2 3
2