#include <cstdio>
#include <cmath>
#include <algorithm>
using namespace std;

double f[3000];
bool hasBomb[3000];

int main() {
    int T;
    scanf("%d", &T);
    while(T--) {
        int n, m;
        scanf("%d%d", &n, &m);
        for(int i=0; i<=n; ++i) {
            hasBomb[i] = false;
            f[i] = 0.0;
        }
        for(int i=0; i<m; ++i) {
            int p;
            scanf("%d", &p);
            hasBomb[p] = true;
        }
        for(int i=0; i<n; ++i) if( hasBomb[i] ) {
            for(int l=0; l   <= i && (l==0||!hasBomb[i-l]); ++l)
            for(int r=0; i+r <  n && (r==0||!hasBomb[i+r]); ++r) {
                if( i-l-1 >= 0 )
                    f[i+r] = max(f[i+r], log2(l+r+1) + f[i-l-1]);
                else
                    f[i+r] = max(f[i+r], log2(l+r+1));
            }
        }
        double z = f[0];
        for(int i=1; i<n; ++i)
            z = max(z, f[i]);
        printf("%.0f\n",floor(1000000 * z));
    }
    return 0;
}