#include <bits/stdc++.h>
using namespace std;
const int N = 1e4+10;
int t,n;
int a[N];
map<int,bool>mp[N];
int main(){
    freopen("sequence.in","r",stdin);
    freopen("sequence.out","w",stdout);
    scanf("%d",&t);
    while(t--){
        scanf("%d",&n);
        for(int i = 1;i <= n;i++)scanf("%d",&a[i]);
        for(int i = 1;i <= n;i++)mp[i].clear();
        for(int i = 1;i <= n;i++){
            for(int j = i+1;j <= n;j++){
                mp[i][a[i]-a[j]] = 1;
            }
        }
        bool f = 0;
        for(int i = n;i >= 1;i--){
            for(int j = i-1;j >= 1;j--){
                if(mp[i][a[j]-a[i]]){
                    printf("Y\n");
                    f = 1;
                    break;
                }
            }
            if(f)break;
        }
        if(!f)printf("N\n");
    }
    
    return 0;
    
}