1 #include<bits/stdc++.h>
 2 using namespace std;
 3 #define pb(x) push_back(x)
 4 #define ll long long
 5 #define mk(x, y) make_pair(x, y)
 6 #define lson l, m, rt<<1
 7 #define mem(a) memset(a, 0, sizeof(a))
 8 #define rson m+1, r, rt<<1|1
 9 #define mem1(a) memset(a, -1, sizeof(a))
10 #define mem2(a) memset(a, 0x3f, sizeof(a))
11 #define rep(i, a, n) for(int i = a; i<n; i++)
12 #define ull unsigned long long
13 typedef pair<int, int> pll;
14 const double PI = acos(-1.0);
15 const double eps = 1e-8;
16 const int mod = 1e9+7;
17 const int inf = 1061109567;
18 const int dir[][2] = { {-1, 0}, {1, 0}, {0, -1}, {0, 1} };
19 const int maxn = 1e5+5;
20 int lnum[maxn<<2], rnum[maxn<<2], maxx[maxn<<2], pre_max[maxn<<2], suf_max[maxn<<2];
21 void pushUp(int rt, int m) {
22     maxx[rt] = max(maxx[rt<<1], maxx[rt<<1|1]);
23     lnum[rt] = lnum[rt<<1];
24     rnum[rt] = rnum[rt<<1|1];
25     suf_max[rt] = suf_max[rt<<1|1];
26     if(suf_max[rt] == (m>>1)&&lnum[rt<<1|1] == rnum[rt<<1])         //如果左区间最右边的数和右区间最左边的数相等
27         suf_max[rt] += suf_max[rt<<1];                              //并且左区间的后缀长度等于这段区间的长度
28     pre_max[rt] = pre_max[rt<<1];
29     if(pre_max[rt] == m-(m>>1) && rnum[rt<<1] == lnum[rt<<1|1])
30         pre_max[rt] += pre_max[rt<<1|1];
31     if(lnum[rt<<1|1] == rnum[rt<<1])
32         maxx[rt] = max(maxx[rt], pre_max[rt<<1|1]+suf_max[rt<<1]);
33 }
34 void build(int l, int r, int rt) {
35     if(l == r) {
36         scanf("%d", &lnum[rt]);
37         rnum[rt] = lnum[rt];
38         maxx[rt] = pre_max[rt] = suf_max[rt] = 1;
39         return ;
40     }
41     int m = l+r>>1;
42     build(lson);
43     build(rson);
44     pushUp(rt, r-l+1);
45 }
46 int query(int L, int R, int l, int r, int rt) {
47     if(L<=l&&R>=r) {
48         return maxx[rt];
49     }
50     int m = l+r>>1;
51     if(R<=m)
52         return query(L, R, lson);
53     if(L>m)
54         return query(L, R, rson);
55     int tmp1 = query(L, m, lson);
56     int tmp2 = query(m+1, R, rson);
57     int tmp3 = 0;
58     if(lnum[rt<<1|1] == rnum[rt<<1])
59         tmp3 = min(pre_max[rt<<1|1], R-m)+min(suf_max[rt<<1], m-L+1);
60     return max(tmp1, max(tmp2, tmp3));
61 }
62 int main()
63 {
64     int n, m;
65     while(cin>>n&&n) {
66         cin>>m;
67         build(1, n, 1);
68         while(m--) {
69             int x, y;
70             scanf("%d%d", &x, &y);
71             printf("%d\n", query(x, y, 1, n, 1));
72         }
73     }
74     return 0;
75 }