1 #include <bits/stdc++.h>
2 using namespace std;
3
4 const int INF = 1<<30;
5 const int maxn = 50+5;
6 const int maxt = 200+5;
7 int N,T,a[maxn],t[maxn],M1,d,M2,e,dp[maxt][maxn],kase;
8 bool has_train[maxt][maxn][2];
9
10
11 void solve(){
12 for(int i=1; i<=N-1; i++) dp[T][i] = INF;
13 dp[T][N] = 0;
14
15 for(int i=T-1; i>=0; i--){
16 for(int j=1; j<=N; j++){
17 dp[i][j] = dp[i+1][j]+1;
18 if(j<N && has_train[i][j][0] && i+t[j]<=T)
19 dp[i][j] = min(dp[i][j],dp[i+t[j]][j+1]);
20 if(j>1 && has_train[i][j][1] && i+t[j-1]<=T)
21 dp[i][j] = min(dp[i][j],dp[i+t[j-1]][j-1]);
22 }
23 }
24
25
26 cout << "Case Number " << ++kase << ": ";
27 if(dp[0][1] >= INF) cout << "impossible\n";
28 else cout << dp[0][1] << endl;
29 }
30
31 int main(){
32
33 while(cin>>N && N){
34 memset(has_train,0,sizeof(has_train));
35 cin >> T;
36 for(int i=1; i<=N-1; i++)
37 cin >> t[i];
38 cin >> M1;
39 for(int i=0; i<M1; i++){
40 cin >> d;
41 for(int j=1; j<=N-1; j++){
42 if(d <= T)
43 has_train[d][j][0] = 1;
44 d += t[j];
45
46 }
47 }
48
49 cin >> M2;
50 for(int i=0; i<M2; i++){
51 cin >> e;
52 for(int j=N-1; j>=1; j--){
53 if(e <= T)
54 has_train[e][j+1][1] = 1;
55 e += t[j];
56 }
57 }
58
59
60 solve();
61 }
62
63 }