A. XXXXX

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int a[100000];
int main()
{
    int t;
    cin>>t;
    while(t--)
    {

        int n,x;
        int sum = 0;
        cin>>n>>x;

        int l = -1;
        int r;
        
        for(int i=1;i<=n;i++)
        {

            int b;
            cin>>b;
            if(b%x)
            {
                if(l==-1)
                l = i;
                
                r = i;
            }
            sum+=b;

        }
        if(sum%x)
        {
            cout<<n<<endl;
        }
        else if(l==-1)
        {
            cout<<-1<<endl;
        }
        else
        {
            cout<<n-min(n-r+1,l)<<endl;
        }

    }
    
}