> #include <stdio.h>
> #include <iostream>
> #include <math.h>
> #include <string.h>
> using namespace std;
> const int maxn=100005;
> int a[maxn+10];
> int in[2*maxn+10];
> int f[maxn+10];
> int dp[30][maxn+10];
> int start[maxn+10];
> int n, q, cnt;
> void buildRmq()
> {
>     for (int i=1; i<=cnt; i++) dp[0][i]=f[i];
>     for (int i=1; (1<<i)<=cnt; i++)
>         for (int j=1; (j+(1<<(i-1)))<=cnt; j++)
>             dp[i][j]=max(dp[i-1][j], dp[i-1][j+1<<(i-1)]);
> }
> int Query(const int &l, const int &r)
> {
>     int x=a[l], y=a[r];
>     int c=in[x], b=in[y];
>     if (c==b) return b-c+1;
>     else if (c+1==b) return max(start[b]-l, r-start[b]+1);
>     else
>     {
>         int m=max(start[c+1]-l, r-start[b]+1);
>         c++, b--;
>         int k=(int)floor(log(b-c+1.0)/log(2.0));
>         return max(m, max(dp[k][c], dp[k][b-(1<<k)+1]));
>     }
> }
> int main()
> {
>     freopen("in.txt", "r", stdin);
>     while (scanf("%d", &n), n)
>     {
>         scanf("%d", &q);
>         memset(f, 0, sizeof(f));
>         a[0]=0;
>         cnt=0;
>         for (int i=1; i<=n; i++)
>         {
>             scanf("%d", &a[i]);
>             a[i]+=maxn;
> 
>             if (a[i] !=a[i-1]) in[a[i]]=++cnt, start[cnt]=i;
>             f[cnt]++;
>         }
>         buildRmq();
>         for (int i=0; i<q; i++)
>         {
>             int x, y;
>             scanf("%d %d", &x, &y);
>             if (x>y) printf("%d\n", Query(y, x));
>             else printf("%d\n", Query(x, y));
>         }
>     }
>     return 0;
> }