#include<iostream>

#include<vector>

#include<algorithm>

using namespace std;
int main()
{
int T;cin>>T;
int N,a; vector<int> v;
while(T)
{
cin>>N;
while(N)
{
cin>>a;
v.push_back(a);
N--;
}
sort(v.begin(),v.end());
cout<<v[v.size()-1]<<endl;
T--;v.clear();
}
return 0;
}