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

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

typedef long double ld;
typedef pair<ld, ld> pdd;

const int MAXN = 5e4;
const int MAXQ = 3e5;

const ld eps = 1e-10;

int N, Q;
vector<pll> A[MAXN+10];
pll B[MAXQ+10];
ld xsum, sqcsum, fsum, psum;
ld ans[MAXN+10];

struct Data
{
    ld slp, dsqc, dx;
    ld dp, df;
    bool operator < (Data ot) const { return slp < ot.slp; }
};

int main()
{
    ios_base::sync_with_stdio(false); cin.tie(NULL);
    
    ll sum=0;
    scanf("%d%d", &N, &Q);

    vector<Data> V;
    for(int i=1; i<=N; i++)
    {
        int t;
        scanf("%d", &t);
        A[i]=vector<pll>(t);

        ll psum=0, csum=0;
        for(int j=0; j<t; j++) scanf("%lld", &A[i][j].first), csum+=A[i][j].first;
        for(int j=0; j<t; j++) scanf("%lld", &A[i][j].second), psum+=A[i][j].second;
        sum+=csum;

        sort(A[i].begin(), A[i].end(), [&](pll p, pll q)
        {
            return p.first*q.second < q.first*p.second;
        });

        ld bef=0;
        ll cval=csum, pval=psum;
        bool flag=false;
        for(int j=0; j<t; j++)
        {
            ld l=bef, r=(ld)A[i][j].first/A[i][j].second*psum;
            l=max(l, (ld)csum);
            if(l+eps < r)
            {
                ld slpl = -cval/l/l, slpr = -cval/r/r;
                ld fl = cval/l-(ld)pval/psum, fr = cval/r-(ld)pval/psum;
                // printf("%.10Lf %.10Lf : %.10Lf %.10Lf / %.10Lf %.10Lf / %lld %lld %lld\n", l, r, slpl, slpr, fl, fr, cval, pval, psum);
                if(!flag)
                {
                    flag=true;
                    xsum+=l;
                    fsum+=fl;
                }
                V.push_back({slpl, sqrt((ld)cval), -l, (ld)pval/psum, -fl});
                V.push_back({slpr, -sqrt((ld)cval), r, -(ld)pval/psum, fr});
            }

            cval-=A[i][j].first;
            pval-=A[i][j].second;
            bef=r;
        }
        if(!flag) xsum+=max(bef, (ld)csum);
    }
    for(int i=1; i<=Q; i++)
    {
        scanf("%lld", &B[i].first);
        B[i].first+=sum;
        B[i].second=i;
    }
    sort(B+1, B+Q+1);

    sort(V.begin(), V.end());
    for(int i=0, j=1; i<V.size(); i++)
    {
        auto [slp, dsqc, dx, dp, df] = V[i];
        ld x=(sqcsum+dsqc)/sqrt(-slp)+(xsum+dx);
        // printf("!%.20Lf : %.20Lf\n", slp, x);
        for(; j<=Q && B[j].first<=x; j++)
        {
            // printf("ANS %lld %lld => %.10Lf %.10Lf %.10Lf\n", B[j].second, B[j].first, sqcsum, psum, fsum);
            if(sqcsum < eps) ans[B[j].second]=fsum;
            else ans[B[j].second]=sqcsum*sqcsum/(B[j].first-xsum)-psum+fsum;
        }

        sqcsum+=dsqc;
        xsum+=dx;
        fsum+=df;
        psum+=dp;
    }

    for(int i=1; i<=Q; i++) printf("%.20Lf\n", ans[i]*2);
}