#include <iostream>
#include <vector>
#include <queue>
using namespace std;

#define pii pair<int, int>
#define x first
#define y second

const int KMAX = 20;
const char nl = '\n';
vector<vector<int>> a(KMAX + 5);
int pos[KMAX + 5];

class MinHeap {
private:
    vector<pii> heap;

    void heapify_up(int index) {
        int parent = (index - 1) / 2;
        if (index > 0 && heap[index].x < heap[parent].x) {
            swap(heap[index], heap[parent]);
            heapify_up(parent);
        }
    }

    void heapify_down(int index) {
        while (true) {
            int left = 2 * index + 1;
            int right = 2 * index + 2;
            int smallest = index;

            if (left < heap.size() && heap[left].x < heap[smallest].x)
                smallest = left;
            if (right < heap.size() && heap[right].x < heap[smallest].x)
                smallest = right;
            if (smallest == index)
                return;

            swap(heap[index], heap[smallest]);
            index = smallest;
        }
    }

public:
    void push(int value, int vector_index) {
        heap.push_back({value, vector_index});
        heapify_up(heap.size() - 1);
    }

    pii pop() {
        pii top = heap.front();
        heap[0] = heap.back();
        heap.pop_back();

        if (!heap.empty()) {
            heapify_down(0);
        }
        return top;
    }

    bool empty() const {
        return heap.empty();
    }
};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    freopen("interclasari.in", "r", stdin);
    freopen("interclasari.out", "w", stdout);

    int k;
    cin >> k;

    int total = 0;
    for (int i = 1; i <= k; ++i) {
        int n;
        cin >> n;
        total += n;
        a[i].resize(n);

        for (int j = 0; j < n; ++j) {
            cin >> a[i][j];
        }
        pos[i] = 0;
    }

    MinHeap heap;
    for (int i = 1; i <= k; ++i) {
        if (!a[i].empty()) {
            heap.push(a[i][0], i);
            pos[i] = 1;
        }
    }

    cout << total << nl;
    for (int i = 0; i < total; ++i) {
        pii top = heap.pop();
        cout << top.x << ' ';
        int s = top.y;
        if (pos[s] < a[s].size()) {
            heap.push(a[s][pos[s]], s);
            pos[s]++;
        }
    }

    cout << nl;
    return 0;
}