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#include <cstdio>
#include <vector>

using Day = std::vector<int>;

Day readDay() {
  Day day;
  int n;
  scanf("%d", &n);
  day.resize(n + 1);
  for (int i = 1; i <= n; ++i) {
    scanf("%d", &day[i]);
  }
  return day;
}

int process(const int& meetings, const Day& day, Day& buffer) {
  Day nextBuffer;
  nextBuffer.resize(meetings + 1);

  for (int i = 1; i < day.size(); ++i) {
    nextBuffer[day[i]] += buffer[i];
  }
  int minimalWorkers = 0;
  for (int i = 1; i < nextBuffer.size(); ++i) {
    if (nextBuffer[i] == 0) {
      nextBuffer[i] = 1;
    }
    minimalWorkers += nextBuffer[i];
  }
  buffer = std::move(nextBuffer);
  return minimalWorkers;
}

int main() {
  int k, n;
  scanf("%d %d\n", &k, &n);
  std::vector<Day> days;
  for (int i = 2; i <= k; ++i) {
    days.emplace_back(readDay());
  }

  int minimalWorkers = days.back().size() - 1;
  Day buffer;
  for (int i = 0; i < days.back().size(); ++i) {
    buffer.push_back(1);
  }
  buffer[0] = 0;

  for (int i = days.size() - 1; 0 <= i; --i) {
    minimalWorkers = std::max(minimalWorkers, process(0 <= i - 1 ? days[i - 1].size() - 1 : n, days[i], buffer));
  }

  printf("%d\n", minimalWorkers);
  return 0;
}