#include <stdio.h>
#include <string.h>

int gold[100001];
int conn[100001];
int *p[100001];

int max(int a, int b){return a>b?a:b;}

int main()
{
    int n, i, k;
    int nn;
    int mx;
    int n1, n2;
    int cnt;

    scanf("%d", &n);

    for(i=0; i<n; i++)
    {
        scanf("%d %d", &k, &nn);

        cnt=0;
        mx = 0;

        memset(gold, -1, sizeof(gold));
        memset(conn, 0, sizeof(conn));

        while(nn--)
        {
            scanf("%d %d", &n1, &n2);

            if(gold[n1] == -1 && gold[n2] == -1)
            {
                gold[n1] = gold[n2] = cnt;
                conn[cnt] += 2;
                p[cnt] = &conn[cnt];
                mx = max(mx, conn[cnt++]);
            }
            else if(gold[n1] > -1 && gold[n2] > -1)
            {
                if(p[gold[n1]] == p[gold[n2]]) continue;

                *p[gold[n1]] += *p[gold[n2]];
                p[gold[n2]] = p[gold[n1]];
                mx = max(mx, *p[gold[n1]]);
            }
            else if(gold[n1] > -1 && gold[n2] == -1)
            {
                gold[n2] = gold[n1];
                (*p[gold[n1]])++;
                mx = max(mx, *p[gold[n1]]);
            }
            else if(gold[n2] > -1 && gold[n1] == -1)
            {
                gold[n1] = gold[n2];
                (*p[gold[n2]])++;
                mx = max(mx, *p[gold[n1]]);
            }
        }
        printf("%d\n", mx);
    }

    return 0;
}