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#include <bits/stdc++.h>

using namespace std;
bool testing = false;
#define F first
#define S second
#define ll long long
#define tc    \
    int t;    \
    cin >> t; \
    while (t--)
#define all(A) A.begin(), A.end()

void fio()
{
    cin.tie(nullptr);
    cout.tie(nullptr);
    ios::sync_with_stdio(false);
}

void file_io(string fname)
{

    freopen((fname + ".in").c_str(), "r", stdin);
    freopen((fname + ".out").c_str(), "w", stdout);
}
void file_i(string fname)
{

    freopen((fname + ".in").c_str(), "r", stdin);
}

void exec_time()
{

    using namespace std::chrono;
    // Get starting timepoint
    static auto start = high_resolution_clock::now();
    static bool end = false;
    // Get ending timepoint
    if (end)
    {
        auto stop = high_resolution_clock::now();

        // Get duration. Substart timepoints to
        // get durarion. To cast it to proper unit
        // use duration cast method
        auto duration = duration_cast<milliseconds>(stop - start);

        cout << "\nExec Time :"
             << duration.count() << " milliseconds\n";
    }
    else
        end = true;
}

// ------------------ Global variables declaration --------------------- //
int x;
int a[] = {12, 15, 15, 19, 24, 31, 53, 59, 60};

// -------------------------------------------------------------------- //

//---------------------------------methods-------------------------------------

//---------------------------------methods-------------------------------------

int main()
{
    // testing = true;
    fio();
    if (testing)
    {
        file_io("test");
        exec_time();
    }
    //-------------------------------solution--------------------------------
    tc
    {
        int n;
        cin >> n;
        int arr[n];
        for (int i = 0; i < n; i++)
        {
            cin >> arr[i];
        }
        int r = 0;
        for (int i = 0; i < n - 1; i++)
        {
            if (arr[i] > arr[i + 1])
                r = max(r, arr[i]);
        }
        cout << r << endl;
    }
    //-----------------------------------------------------------------------
    if (testing)

        exec_time();

    return 0;
}