#include <bits/stdc++.h>
using namespace std;
vector<pair<pair<int, int>, int> > quer[100010];
int par[100010], sz[100010], in[100010], val[100010],
    ct = 0, tree[4 * 100010], lazy[4 * 100010], visited[100010];
vector<int> graph[100010];
pair<int, int> rng[100010];
int mult(int a, int b) { return 1LL * a * b % 1000000007; }
int add(int a, int b) { return (a + b) % 1000000007; }
int root(int a) {
  while (par[a] != a) {
    a = par[a];
    par[a] = par[par[a]];
  }
  return a;
}
void unionit(int a, int b) {
  int x = root(a);
  int y = root(b);
  if (sz[x] < sz[y]) {
    par[x] = y;
    sz[y] += sz[x];
  } else {
    par[y] = x;
    sz[x] += sz[y];
  }
}
void dfs(int s, int par) {
  visited[s] = 1;
  in[s] = ct++;
  for (auto to : graph[s]) {
    if (to != par) {
      dfs(to, s);
    }
  }
  rng[s] = make_pair(in[s], ct - 1);
}
void push(int low, int high, int node) {
  if (lazy[node]) {
    tree[node] = add(tree[node], mult(high - low + 1, lazy[node]));
    if (low != high) {
      lazy[2 * node] = add(lazy[2 * node], lazy[node]);
      lazy[2 * node + 1] = add(lazy[2 * node + 1], lazy[node]);
    }
    lazy[node] = 0;
  }
}
void update(int low, int high, int begin, int end, int val, int node) {
  push(low, high, node);
  if (low > end || high < begin) return;
  if (low >= begin & high <= end) {
    lazy[node] = val;
    push(low, high, node);
    return;
  }
  int mid = (low + high) / 2;
  update(low, mid, begin, end, val, 2 * node);
  update(mid + 1, high, begin, end, val, 2 * node + 1);
  tree[node] = add(tree[2 * node], tree[2 * node + 1]);
}
int query(int low, int high, int begin, int end, int node) {
  push(low, high, node);
  if (low > end || high < begin) return 0;
  if (low >= begin && high <= end) return tree[node];
  int mid = (low + high) / 2;
  return add(query(low, mid, begin, end, 2 * node),
             query(mid + 1, high, begin, end, 2 * node + 1));
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) par[i] = i, sz[i] = 1;
  for (int i = 0; i < n; i++) {
    int k;
    cin >> k;
    for (int j = 0; j < k; j++) {
      int v, x;
      cin >> v >> x;
      x = (x + 1000000007) % 1000000007;
      v--;
      int y = val[root(v)];
      unionit(v, i);
      graph[y].push_back(i);
      graph[i].push_back(y);
      quer[i].push_back(make_pair(make_pair(v, x), y));
    }
    val[root(i)] = i;
  }
  for (int i = n - 1; i >= 0; i--) {
    if (!visited[i]) {
      dfs(i, -1);
    }
  }
  long long ans = 0;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < quer[i].size(); j++) {
      int y = query(0, n - 1, in[quer[i][j].first.first],
                    in[quer[i][j].first.first], 1);
      ans = add(ans, add(y, quer[i][j].first.second));
      update(0, n - 1, rng[quer[i][j].second].first,
             rng[quer[i][j].second].second, add(y, quer[i][j].first.second), 1);
    }
  }
  cout << ans << '\n';
}
