/*input
1 5
0 0 6
*/
#pragma GCC optimize ("O3")
#pragma GCC target("avx,avx2,fma")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
template <typename T>
using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int M;
ll L;
cin >> M >> L;
ll A[2 * M + 1];
for (int i = 0; i <= 2 * M; i++)
cin >> A[i];
//array<array<pair<ll, ll>, 300>, 301> v, w;
array<pair<ll, ll>, 300> v, w;
// for (int m = 1; m <= M; m++)
// {
// for (int k = 0; k < m; k++)
// v[m][k] = { -3e18, -3e18};
// v[m][0] = {0, 0};
// }
for (int k = 0; k < M; k++)
v[k] = { -3e18, -3e18};
v[0] = {0, 0};
ll ret = -1;
for (ll i = 1; i <= M; i++)
{
w = v;
//for (ll m = 1; m <= M; m++)
for (ll k = 0; k < M; k++)
{
ll x = v[k].first;
//ll x = v[m][k].first;
ll mx = (L - x) / i;
mx = min(mx, A[i + M]);
for (ll c = mx; c >= 0 && c >= mx - M; c--)
{
ll val = x + i * c;
ll cnt = v[k].second + c;
w[val % M] = max(w[val % M], {val, cnt});
// for (ll md = 1; md <= M; md++)
// {
// ll vv = val % md;
// w[md][vv] = max(w[md][vv], {val, cnt});
// }
}
}
v = w;
}
//for (int m = 1; m <= M; m++)
for (int k = 0; k < M; k++)
if (v[k].first == L)
ret = max(ret, v[k].second);
if (ret < 0)
cout << "impossible\n";
else
cout << ret + A[M] << "\n";
}
