#include <bits/stdc++.h>

#define fst first
#define snd second
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(a, v) memset( a , v , sizeof(a) )
#define pb push_back
#define mp make_pair
#define sz size()
#define FORN( i , s , n ) for( int i = (s) ; i < (n) ; i++ )
#define FOR( i , n ) FORN( i , 0 , n )
#define FORIT( i , x ) for( typeof x.begin() i = x.begin() ; i != x.end() ; i++ )
#define trace(x)    cout << #x << ": " << x << endl;
#define trace2(x, y) cout << #x << ": " << x << " | " << #y << ": " << y << endl;
#define trace3(x, y, z) cerr << #x << ": " << x << " | " << #y << ": " << y << " | " << #z << ": " << z << endl;
#define read ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);

using namespace std;

typedef long long int64;
typedef vector <int> vi;
typedef pair <int,int> ii;
typedef vector <string> vs;
typedef vector <ii> vii;

int W[105];
int H[105];

int L[105];
double R[105];

double maxR[25010];

int main(){
    int T,N;
    double P;
    cin>>T;
    FORN(caso, 1, T+1){
        printf("Case #%d: ", caso);
        cin>>N>>P;
        double aux = 0;
        FOR(i,N) {
            cin>>W[i]>>H[i];
            L[i] = min(W[i], H[i]) * 2;
            R[i] = sqrt( W[i]*W[i] + H[i]*H[i] ) * 2.0;
            P -= 2.0*(W[i] + H[i]);
            aux += 2.0*(W[i] + H[i]);
        }

        FOR(i, 25005) maxR[i] = -1e18;

        maxR[0] = 0.0;


        FOR(i,N) FORN(j, L[i], 25005) {
            maxR[j] = max ( maxR[j], maxR[j - L[i]] + R[i] );
        }

        double ans = 0;
        FOR(i,min((int)P+1,25005)) ans = max ( ans, min( P, maxR[i] ) );

        printf("%.08f\n",ans+aux);

    }
    return 0;
}