#include <vector>
#include <algorithm>
#include <set>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
typedef tree<int,null_type,less_equal<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
int sequence(const int n,const vector<int> arr){
int ans = 0;
vector<vector<int>> cnt(n+1,vector<int>(n+1,0)); // [pos][numer]
for (int pos = 1;pos<=n;pos++){
for (int num = 0;num<=n;num++){
cnt[pos][num]=cnt[pos-1][num]+int(arr[pos-1]==num);
}
}
for (int l = 0;l<n;l++){
ordered_set os;
for (int r = l;r<n;r++){
os.insert(arr[r]);
vector<int> data(r-l+1);
int s = r-l+1;
int mid1 = *os.find_by_order(s/2);
int mid2 = *os.find_by_order((s-1)/2);
ans = max(cnt[r+1][mid1]-cnt[l][mid1],ans);
ans = max(cnt[r+1][mid2]-cnt[l][mid2],ans);
}
}
return ans;
}
