#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#include <iostream>
#include <unordered_map>
#include <random>
#include <algorithm>

using namespace std;
typedef long long ll;
unordered_map<int,int> pri;
int a[100010][10],b[100010][10],A[100010],sz[100010];
vector<int> c[100010],pp;
unordered_map<int,ll> hs;
unordered_map<ll,bool> se,zob;
ll inf = 1000000000000000;
bool ok = false;
vector<int> ans;
bool used[100010];
void solve(int pos,int target_num,vector<int> now,ll val){
    if(ok) return;
    if(now.size()==target_num){
        // cout << "result = :";
        // for(int x:now) cout << x << " ";
        // cout << "\n"; 
        // cout << "value = " << val << "\n";
        if(zob.find(val)==zob.end()){
            ok = true;
            ans = now;
        }
        return;
    }
    if(now.size() + pp.size() - pos==target_num){
        val ^= hs[pp[pos]]; now.push_back(pp[pos]);
        solve(pos + 1,target_num,now,val);
    }else{
        for(int i=pos;i<(int)pp.size() + (int)now.size() - target_num + 1;i++){
            val ^= hs[pp[i]]; now.push_back(pp[i]);
            solve(i + 1,target_num,now,val);
            val ^= hs[pp[i]]; now.pop_back();
        }
    }
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int i,j,n; cin >> n;
    for(i=0;i<n;i++){
        cin >> sz[i];
        A[i] = 1;
        for(j=0;j<sz[i];j++){
            cin >> a[i][j] >> b[i][j];
            pri[a[i][j]] = max(pri[a[i][j]],b[i][j]);
            for(int k=0;k<b[i][j];k++) A[i] *= a[i][j]; 
        }
    }
    for(i=0;i<n;i++){
        for(j=0;j<sz[i];j++){
            if(pri[a[i][j]]==b[i][j]) c[i].push_back(a[i][j]);
        }
    }
    std::random_device seed_gen;
    std::default_random_engine engine(seed_gen());

    // 0以上inf以下の値を等確率で発生させる
    std::uniform_int_distribution<ll> dist(0, inf);
    for(auto x:pri) hs[x.first] = dist(engine);
    int mx = -1;
    for(i=0;i<n;i++){
        mx = max(mx,(int)c[i].size());
        ll val = 0;
        for(int p:c[i]) val ^= hs[p];
        if(se.find(val)!=se.end()) continue;
        se[val] = true;
        for(j=0;j<(1<<c[i].size());j++){
            ll val2 = 0;
            for(int k=0;k<c[i].size();k++){
                if(j>>k&1) val2 ^= hs[c[i][k]];
            }
            zob[val2] = true;
        }
    }
    if(mx==pri.size()){
        cout << -1 << "\n";
        return 0;
    }
    for(auto x:pri) pp.push_back(x.first);
    std::random_device seed_gen2;
    std::default_random_engine engine2(seed_gen2());
    shuffle(pp.begin(),pp.end(),engine2);
    for(i=1;i<=10;i++){
        vector<int> now;
        if(!ok) solve(0,i,now,0);
    }
    cout << ans.size() << "\n";
    for(i=0;i<n;i++) used[i] = false;
    for(int p:ans){
        vector<int> vec;
        for(i=0;i<n;i++){
            if(used[i]) continue;
            bool f = true;
            for(int q:c[i]){
                if(p==q) f = false;
            }
            if(f){
                vec.push_back(A[i]); used[i] = true;
            }
        }
        cout << vec.size() << " ";
        for(int X:vec) cout << X << " ";
        cout << "\n";
    }
}