#include<cstdio>

#include<set>

#include<cstdlib>

using namespace std;

const int maxn = ;

set<int> s[maxn];

int n;

int main() {

    while(~scanf("%d", &n)) {

        int cnt;

        for(int i = ; i < n; i++) {

            if(!s[i].empty())s[i].clear();

            scanf("%d", &cnt);

            int x;

            for(int j = ; j < cnt; j++) {

                scanf("%d", &x);

                s[i].insert(x);

            }

        }

        scanf("%d", &cnt);

        int u,v;

        for(int i = ; i < cnt; i++) {

            scanf("%d%d", &u, &v);

            u--,v--;

            int same = ;

            int size_s1 = s[u].size();

            int size_s2 = s[v].size();

            set<int>::iterator it;

            for(it = s[u].begin(); it != s[u].end(); it++) {

                if(s[v].find(*it) != s[v].end()) {

                    same++;

                }

            }

            int nc = same;

            int nt = size_s1+size_s2-same;

            double ans = (nc*1.0)/(nt*1.0)*;

            printf("%.2lf%%\n", ans);

        }

    }

    return ;

}