#include<bits/stdc++.h>
using namespace std;

const int N = 1e6+10;
int lt[N];
int rt[N];
int hsh[N];
int main(){
    int t;
    cin >> t;
    assert(1<=t && t <= 10);
    while(t--){
        int n, m;
        cin >> n >> m;
        assert(n >= 1 && n <= 1000000);
        assert(m >= 2  && m <= 1000000);
        for(int i = 0; i <= n; ++i){
            hsh[i] = 0;
        }
        int x;
        for(int i = 0; i < m; ++i){
            cin >> x;
            hsh[x]++;
        }

        stack <int> s;
        for(int i = 0; i <= n; ++i){
            while(!s.empty() && hsh[s.top()] > hsh[i]){
                rt[s.top()] = i;
                s.pop();
            }
            s.push(i);
        }
        while(!s.empty()){
            rt[s.top()] = n+1;
            s.pop();
        }
        for(int i = n; i >= 0; --i){
            while(!s.empty() && hsh[s.top()] > hsh[i]){
                lt[s.top()] = i;
                s.pop();
            }
            s.push(i);
        }
        while(!s.empty()){
            lt[s.top()] = -1;
            s.pop();
        }
        long long int ans = 0;
        for(int i = 0; i <= n; ++i){
        //  cout << lt[i] << " " << rt[i] << endl;
            ans = max(hsh[i] * 1LL * (rt[i] - lt[i] - 1), ans);
        }
        cout << ans << endl;
    }
}