#include<iostream>
#include<iomanip>
using namespace std;
int main(void)
{
int n, m, i;
double a[100], max;
cin >> n;
while (n--) {
cin >> m;
for (i = 0; i < m; i++)
cin >> a[i];
max = a[0];
for (i = 1; i < m; i++)
if (a[i] > max)
max = a[i];
cout << fixed << setprecision(2) << max << endl;
}
return 0;
}