#include <bits/stdc++.h>
using namespace std;

//#define int long long
#define f(i,a,b) for(int i = (a); i < (b); ++i)

using ll = long long;

signed main()
{
    ios_base::sync_with_stdio(0);
    int n;
    cin >> n;
    map<int, ll> profit;
    vector<ll> dp(n + 1);
    dp[0] = 0;
    for (int i = 1; i <= n; ++i)
    {
        dp[i] = dp[i - 1];
        int m;
        cin >> m;
        vector<pair<int, ll>> cranes(m);
        for (int j = 0; j < m; ++j)
        {
            cin >> cranes[j].first >> cranes[j].second;
            if (profit.find(cranes[j].first) != profit.end())
            {
                dp[i] = max(dp[i], profit[cranes[j].first] + cranes[j].second);
            }
        }
        for (int j = 0; j < m; ++j)
        {
            if (profit.find(cranes[j].first) == profit.end())
            {
                profit[cranes[j].first] = dp[i] - cranes[j].second;
            }
            else
            {
                profit[cranes[j].first] = max(profit[cranes[j].first], dp[i] - cranes[j].second);
            }
        }
    }
    cout << dp.back();
    return 0;
}