2346: Xors on Segments
[Creator : ]
Description
time limit per test
10 secondsmemory limit per test
512 megabytesinput
standard inputoutput
standard outputYou are given an array with n integers ai and m queries. Each query is described by two integers (lj,rj).
Let's define the function . The function is defined for only u≤v.
For each query print the maximal value of the function f(ax,ay) over all lj≤x,y≤rj, ax≤ay.
Input
The first line contains two integers n,m (1≤n≤5·104, 1≤m≤5·103) − the size of the array and the number of the queries.
The second line contains n integers ai (1≤ai≤106) − the elements of the array a.
Each of the next m lines contains two integers lj,rj (1≤lj≤rj≤n) — the parameters of the j-th query.
Output
For each query print the value aj on a separate line − the maximal value of the function f(ax,ay) over all lj≤x,y≤rj, ax≤ay.
Examples
Input
6 3
1 2 3 4 5 6
1 6
2 5
3 4
Output
7
7
7
Input
1 1
1
1 1
Output
1
Input
6 20
10 21312 2314 214 1 322
1 1
1 2
1 3
1 4
1 5
1 6
2 2
2 3
2 4
2 5
2 6
3 4
3 5
3 6
4 4
4 5
4 6
5 5
5 6
6 6
Output
10
21313
21313
21313
21313
21313
21312
21313
21313
21313
21313
2314
2315
2315
214
215
323
1
323
322