#include <bits/stdc++.h>
using namespace std;
void dfs(vector<int> &ans, bool &ok, int &cnt, vector<unsigned long long> &hash, vector<unsigned long long> &ng, vector<int> &curr, unsigned long long ch, int sz, int p){
  if (p == -1){
    if (curr.size() == sz){
      auto itr = lower_bound(ng.begin(), ng.end(), ch);
      if (itr == ng.end()){
        ans = curr;
        ok = true;
      } else if (*itr != ch){
        ans = curr;
        ok = true;
      }
    }
  } else {
    if (curr.size() < sz){
      curr.push_back(p);
      dfs(ans, ok, cnt, hash, ng, curr, ch ^ hash[p], sz, p - 1);
      curr.pop_back();
    }
    if (ok){
      return;
    }
    dfs(ans, ok, cnt, hash, ng, curr, ch, sz, p - 1);
  }
}
int main(){
  mt19937 mt(chrono::steady_clock::now().time_since_epoch().count());
  int N;
  cin >> N;
  vector<int> m(N);
  vector<vector<int>> p(N), e(N);
  for (int i = 0; i < N; i++){
    cin >> m[i];
    p[i] = vector<int>(m[i]);
    e[i] = vector<int>(m[i]);
    for (int j = 0; j < m[i]; j++){
      cin >> p[i][j] >> e[i][j];
    }
  }
  vector<int> P;
  for (int i = 0; i < N; i++){
    for (int j = 0; j < m[i]; j++){
      P.push_back(p[i][j]);
    }
  }
  sort(P.begin(), P.end());
  P.erase(unique(P.begin(), P.end()), P.end());
  int cnt = P.size();
  for (int i = 0; i < N; i++){
    for (int j = 0; j < m[i]; j++){
      p[i][j] = lower_bound(P.begin(), P.end(), p[i][j]) - P.begin();
    }
  }
  vector<int> mx(cnt, -1);
  for (int i = 0; i < N; i++){
    for (int j = 0; j < m[i]; j++){
      mx[p[i][j]] = max(mx[p[i][j]], e[i][j]);
    }
  }
  vector<vector<int>> s(N);
  for (int i = 0; i < N; i++){
    for (int j = 0; j < m[i]; j++){
      if (mx[p[i][j]] == e[i][j]){
        s[i].push_back(p[i][j]);
      }
    }
  }
  bool ok = true;
  for (int i = 0; i < N; i++){
    if (s[i].size() == cnt){
      ok = false;
    }
  }
  if (!ok){
    cout << -1 << endl;
  } else {
    vector<unsigned long long> hash(cnt, 0);
    for (int i = 0; i < cnt; i++){
      for (int j = 0; j < 64; j++){
        hash[i] *= 2;
        hash[i] += mt() % 2;
      }
    }
    vector<unsigned long long> ng;
    for (int i = 0; i < N; i++){
      int cnt2 = s[i].size();
      for (int j = 0; j < (1 << cnt2); j++){
        int sz = __builtin_popcount(j);
        unsigned long long S = 0;
        for (int k = 0; k < cnt2; k++){
          if ((j >> k & 1) == 1){
            S ^= hash[s[i][k]];
          }
        }
        ng.push_back(S);
      }
    }
    sort(ng.begin(), ng.end());
    ng.erase(unique(ng.begin(), ng.end()), ng.end());
    return 0;
    vector<int> ans;
    for (int i = 1; i <= 10; i++){
      vector<int> curr;
      unsigned long long chh = 0;
      bool ok2 = false;
      dfs(ans, ok2, cnt, hash, ng, curr, chh, i, cnt - 1);
      if (ok2){
        break;
      }
    }
    vector<int> A(N, 1);
    for (int i = 0; i < N; i++){
      for (int j = 0; j < m[i]; j++){
        for (int k = 0; k < e[i][j]; k++){
          A[i] *= P[p[i][j]];
        }
      }
    }
    int k = ans.size();
    vector<vector<int>> S(k);
    for (int i = 0; i < N; i++){
      for (int j = 0; j < k; j++){
        bool ok2 = true;
        int cnt2 = s[i].size();
        for (int l = 0; l < cnt2; l++){
          if (s[i][l] == ans[j]){
            ok2 = false;
          }
        }
        if (ok2){
          S[j].push_back(A[i]);
          break;
        }
      }
    }
    cout << k << endl;
    for (int i = 0; i < k; i++){
      int n = S[i].size();
      cout << n;
      for (int j = 0; j < n; j++){
        cout << ' ' << S[i][j];
      }
      cout << endl;
    }
  }
}