#include <bits/stdc++.h>
using namespace std;
const int mod = 1000000007;
const int N = 3e5, M = N;
template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {
  os << "[";
  for (int i = 0; i < v.size(); ++i) {
    if (i) os << ", ";
    os << v[i];
  }
  os << "]\n";
  return os;
}
template <typename T>
ostream& operator<<(ostream& os, const set<T>& v) {
  os << "{";
  for (auto it : v) {
    os << it;
    if (it != *v.rbegin()) os << ", ";
  }
  os << "}\n";
  return os;
}
template <typename T, typename second>
ostream& operator<<(ostream& os, const map<T, second>& v) {
  os << "{";
  for (auto it : v) {
    os << "(" << it.first << " : " << it.second << ")";
    if (it != *v.rbegin()) os << ", ";
  }
  os << "}\n";
  return os;
}
template <typename T, typename second>
ostream& operator<<(ostream& os, const pair<T, second>& v) {
  os << "(";
  os << v.first << ", " << v.second << ")";
  return os;
}
template <typename T>
inline istream& operator>>(istream& in, vector<T>& a) {
  for (auto& x : a) in >> x;
  return in;
}
namespace input {
template <class T>
void re(complex<T>& x);
template <class T1, class T2>
void re(pair<T1, T2>& p);
template <class T>
void re(vector<T>& a);
template <class T, size_t SZ>
void re(array<T, SZ>& a);
template <class T>
void re(T& x) {
  cin >> x;
}
void re(double& x) {
  string t;
  re(t);
  x = stod(t);
}
void re(long double& x) {
  string t;
  re(t);
  x = stold(t);
}
template <class Arg, class... Args>
void re(Arg& first, Args&... rest) {
  re(first);
  re(rest...);
}
template <class T>
void re(complex<T>& x) {
  T a, b;
  re(a, b);
  x = cd(a, b);
}
template <class T1, class T2>
void re(pair<T1, T2>& p) {
  re(p.f, p.s);
}
template <class T>
void re(vector<T>& a) {
  for (int i = 0; i < (int)a.size(); i++) re(a[i]);
}
template <class T, size_t SZ>
void re(array<T, SZ>& a) {
  for (int i = 0; i < SZ; i++) re(a[i]);
}
}  // namespace input
using namespace input;
namespace output {
template <class T1, class T2>
void pr(const pair<T1, T2>& x);
template <class T, size_t SZ>
void pr(const array<T, SZ>& x);
template <class T>
void pr(const vector<T>& x);
template <class T>
void pr(const set<T>& x);
template <class T1, class T2>
void pr(const map<T1, T2>& x);
template <class T>
void pr(const T& x) {
  cout << x;
}
template <class Arg, class... Args>
void pr(const Arg& first, const Args&... rest) {
  pr(first);
  pr(rest...);
}
template <class T1, class T2>
void pr(const pair<T1, T2>& x) {
  pr("{", x.first, ", ", x.second, "}");
}
template <class T>
void prContain(const T& x) {
  pr("{");
  bool fst = 1;
  for (const auto& a : x) pr(!fst ? ", " : "", a), fst = 0;
  pr("}\n");
}
template <class T, size_t SZ>
void pr(const array<T, SZ>& x) {
  prContain(x);
}
template <class T>
void pr(const vector<T>& x) {
  prContain(x);
}
template <class T>
void pr(const set<T>& x) {
  prContain(x);
}
template <class T1, class T2>
void pr(const map<T1, T2>& x) {
  prContain(x);
}
void ps() { pr("\n"); }
template <class Arg>
void ps(const Arg& first) {
  pr(first);
  ps();
}
template <class Arg, class... Args>
void ps(const Arg& first, const Args&... rest) {
  pr(first, " ");
  ps(rest...);
}
}  // namespace output
using namespace output;
void run_case() {
  long long int t, i, j, k, p, x, y, u, n, m, w;
  re(n, m);
  vector<int> vis(4 * n, 0);
  vector<int> v;
  for (int i = 0; i < m; i++) {
    re(x, y);
    if (!vis[x] && !vis[y]) {
      vis[x] = vis[y] = 1;
      v.push_back(i + 1);
    }
  }
  if (v.size() >= n) {
    ps("Matching");
    for (int i = 0; i < n; i++) cout << v[i] << " ";
    cout << endl;
  } else {
    ps("Indset");
    for (int i = 1, j = 1; j <= n; i++)
      if (!vis[i]) cout << i << " ", j++;
    cout << endl;
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  int t = 1;
  cin >> t;
  for (int T = 1; 1 < t + 1 ? T < t + 1 : T > t + 1;
       1 < t + 1 ? T += 1 : T -= 1) {
    run_case();
  }
  return 0;
}
