You are the proud... never mind, just solve this problem.
There are $n$ intervals $[l_1, r_1], [l_2, r_2], \ldots [l_n, r_n]$. For each $x$ from $0$ to $2^m - 1$, find the number, modulo $998\,244\,353$, of sequences $a_1, a_2, \ldots a_n$ such that:
$l_i \leq a_i \leq r_i$for all$i$from$1$to$n$;$a_1 \oplus a_2 \oplus \ldots \oplus a_n = x$, where$\oplus$denotes the bitwise XOR operator.
Input
Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 10^4$). The description of the test cases follows.
The first line contains two integers $n$ and $m$ ($1 \leq n \leq 2 \cdot 10^5$, $1 \leq m \leq 18$).
The $i$-th of the next $n$ lines contains two integers $l_i$ and $r_i$ ($0 \leq l_i \leq r_i \lt 2^m$).
It is guaranteed that the sum of $n$ over all test cases does not exceed $2 \cdot 10^5$, and the sum of $2^m$ over all test cases does not exceed $2^{18}$.
Output
For each $x$ from $0$ to $2^m - 1$, let:
$f_x$be the number of valid sequences, modulo$998\,244\,353$;$g_x = f_x \cdot 2^x \mod 998\,244\,353$.
Here, $f_x$ and $g_x$ are both integers in the interval $[0, 998\,244\,352]$.
Let $h = g_0 \oplus g_1 \oplus \ldots \oplus g_{2^m - 1}$.
Output a single integer — the value of $h$ itself. Do not perform a modulo operation.
Note
For the first test case, the values of $f_x$ are as follows:
$f_0 = 2$, because there are$2$valid sequences:$[1, 1]$and$[2, 2]$;$f_1 = 2$, because there are$2$valid sequences:$[0, 1]$and$[2, 3]$;$f_2 = 2$, because there are$2$valid sequences:$[0, 2]$and$[1, 3]$;$f_3 = 3$, because there are$3$valid sequences:$[0, 3]$,$[1, 2]$, and$[2, 1]$.
The values of $g_x$ are as follows:
$g_0 = f_0 \cdot 2^0 = 2 \cdot 2^0 = 2$;$g_1 = f_1 \cdot 2^1 = 2 \cdot 2^1 = 4$;$g_2 = f_2 \cdot 2^2 = 2 \cdot 2^2 = 8$;$g_3 = f_3 \cdot 2^3 = 3 \cdot 2^3 = 24$.
Thus, the value to output is $2 \oplus 4 \oplus 8 \oplus 24 = 22$.
For the second test case, the values of $f_x$ are as follows:
$f_{0} = 120$;$f_{1} = 120$;$f_{2} = 119$;$f_{3} = 118$;$f_{4} = 105$;$f_{5} = 105$;$f_{6} = 106$;$f_{7} = 107$.
样例
4
2 2
0 2
1 3
5 3
3 7
1 3
0 2
1 5
3 6
10 14
314 1592
653 5897
932 3846
264 3383
279 5028
841 9716
939 9375
105 8209
749 4459
230 7816
1 5
0 29
22
9812
75032210
1073741823
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