1 #include <stdio.h>
 2 #include <string.h>
 3 #include <iostream>
 4 #include <algorithm>
 5 #include <stdlib.h>
 6 #include <vector>
 7 #include <queue>
 8 #include <stack>
 9 #define loop(s,i,n) for(i = s;i < n;i++)
10 #define cl(a,b) memset(a,b,sizeof(a))
11 int num[100005],b[100005],rt[100005],lt[100005],a[100005],maxd[100005][17];
12 using namespace std;
13 void init(int n)
14 {
15     int i,j;
16     for(i = 1;i <= n;i++)
17     maxd[i][0] = a[i];
18
19     for(j = 1;(1<<j) <= n;j++)
20     {
21         for(i = 1;i+(1<<j)-1<=n;i++)
22         {
23             maxd[i][j] = max(maxd[i][j-1],maxd[i+(1<<(j-1))][j-1]);
24         }
25     }
26 }
27 int maxrmq(int l,int r)
28 {
29     int k = 0;
30     while(1<<(k+1) <= r-l+1)k++;
31     return max(maxd[l][k],maxd[r-(1<<k)+1][k]);
32
33 }
34 int main()
35 {
36     int n,q;
37
38     while(scanf("%d",&n)&&n)
39     {
40         int i,j;
41         scanf("%d",&q);
42         loop(1,i,n+1)
43         {
44             scanf("%d",&b[i]);
45         }
46         int cnt,leap;
47         cnt = 1;
48         leap = b[1];
49         for(i = 0;i <= n;i++)
50         a[i] = num[i] = 0;
51         lt[1] = 1;
52         for(i = 1;i <= n;i++)
53         {
54             if(leap != b[i])
55             rt[cnt] = i-1,cnt++,lt[cnt] = i,leap = b[i];
56             num[i] = cnt;
57             a[cnt]++;
58         }
59         rt[cnt] = n;
60         init(cnt);
61
62         while(q--)
63         {
64             int l,r,a,b,c;
65             scanf("%d %d",&l,&r);
66             if(num[l] == num[r])
67             b = r-l+1;
68             else if(num[r]-num[l] > 1)
69             {
70                 a = rt[num[l]]-l+1;
71                 b = r-lt[num[r]]+1;
72                 c = maxrmq(num[l]+1,num[r]-1);
73                 b = max(a,b);
74                 b = max(b,c);
75             }
76             else
77             {
78                 a = rt[num[l]]-l+1;
79                 b = r-lt[num[r]]+1;
80                 b = max(a,b);
81             }
82
83             printf("%d\n",b);
84         }
85     }
86     return 0;
87 }