1 #include <bits/stdc++.h>
 2 using namespace std;
 3
 4 typedef long long LL;
 5 const int maxn = 100100;
 6
 7 int n, m, q;
 8 int a[maxn];
 9 int h[maxn], hcnt;
10
11 int l[maxn], r[maxn], v[maxn];
12 int dp[maxn][33];
13
14 void st(int* b) {
15     for(int i = 1; i <= m; i++) dp[i][0] = b[i];
16     int k = int(log(n+1.0)/log(2.0));
17     for(int j = 1; j <= k; j++) {
18         for(int i = 1; i + (1 << j) - 1 <= m; i++) {
19             dp[i][j] = max(dp[i][j-1], dp[i+(1<<(j-1))][j-1]);
20         }
21     }
22 }
23
24 int query(int l, int r) {
25     int k = int(log(r-l+1.0)/log(2.0));
26     return max(dp[l][k], dp[r-(1<<k)+1][k]);
27 }
28
29 int id(int x) {
30     return lower_bound(h, h+hcnt, x) - h + 1;
31 }
32
33 int main() {
34     // freopen("in", "r", stdin);
35     while(~scanf("%d",&n) && n) {
36         scanf("%d", &q);
37         memset(l, 0, sizeof(l));
38         memset(r, 0, sizeof(r));
39         memset(v, 0, sizeof(v));
40         m = -1;
41         int pre = -1, ll = 1, rr, cnt = 0;
42         for(int i = 1; i <= n; i++) {
43             scanf("%d", &a[i]);
44             h[i-1] = a[i];
45         }
46         sort(h, h+n); hcnt = unique(h, h+n) - h;
47         for(int i = 1; i <= n; i++) a[i] = id(a[i]);
48         for(int i = 1; i <= n; i++) {
49             if(pre != a[i]) {
50                 l[++m] = ll, r[m] = i - 1;
51                 v[m] = r[m] - l[m] + 1;
52                 pre = a[i];
53                 ll = i;
54                 cnt = 1;
55             }
56             else rr++, cnt++;
57         }
58         l[++m] = ll, r[m] = n;
59         v[m] = r[m] - l[m] + 1;
60         st(v);
61         while(q--) {
62             scanf("%d %d", &ll, &rr);
63             if(a[ll] == a[rr]) {
64                 cout << rr - ll + 1 << endl;
65                 continue;
66             }
67             int ret = max(0, r[a[ll]]-ll+1);
68             ret = max(ret, rr-l[a[rr]]+1);
69             if(a[ll] + 1 <= a[rr] - 1) ret = max(ret, query(a[ll]+1, a[rr]-1));
70             cout << ret << endl;
71         }
72     }
73     return 0;
74 }