Here is my code

include

include

include

include

include

using namespace std;

int main() {

int n ;
cin >> n;
int q ;
cin >> q;
vector<vector<int>> arr(n);  

for (int i = 0; i < n; i++) {
    int k ;
    cin >> k;

    arr[i].resize(k);

    for (int j = 0; j < k; j++) {
        cin >> arr[i][j];
    }
}

for (int j = 0 ; j < q ; j++) {
    int x, y ;
    cin >> x >> y;
    cout << arr[x][y] << endl;
}
return 0;

}