
#include <iostream>
using namespace std;
const int N = 10000010;
int n, m;
int a[N];
int f[N];
int main()
{
int t;
cin >> t;
while (t -- )
{
cin >> n >> m;
for (int i = 0; i < m; i ++ ) cin >> a[i];
f[1] = 0;
for (int i = 2; i <= n; i ++ ) f[i] = (f[i - 1] + a[(n - i) % m]) % i;
cout << f[n] << endl;
}
return 0;
}