#include<bits/stdc++.h> using namespace std; int main(){ int t; cin>>t; while(t--){ int n,a[20]; cin>>n; for(int i=1;i<=n;i++) cin>>a[i]; sort(a+1,a+n+1); int n1=a[1],n2=a[2]; for(int i=2;i<=n;i++){ if(a[i]!=n1){ n2=a[i]; break; } } if(n1==n2) cout<<"NO"<<endl; else cout<<n2<<endl; } return 0; }