#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
using namespace std;
using pii = pair<int, int>;
const int MOD = 1e9 + 7, N = 2e3 + 10;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long n;
  cin >> n;
  vector<pair<long long, long long>> v(n);
  for (long long i = 0; i < n; i++) {
    long long x;
    cin >> x;
    long long cm = -1;
    long long salary;
    for (long long i = 0; i < x; i++) {
      cin >> salary;
      if (salary > cm) cm = salary;
    }
    v[i].first = cm;
    v[i].second = x;
  }
  sort(v.begin(), v.end());
  long long sum = 0;
  for (long long i = 0; i < n; i++) {
    sum += (v[n - 1].first - v[i].first) * v[i].second;
  }
  cout << sum;
}
