#include <iostream>

using namespace std;

int main()
{
    int t,count;
    double score,max = -1;
    cin >> t;
    for (int i = 1; i <= t; i++)
    {
        cin >> count;
        max = -1;
        while (count--)
        {    
            cin >> score;
            max = max > score ? max : score;
        }
        printf("%.2lf\n", max);
    }
}