#include <bits/stdc++.h>
#undef KEV
using namespace std;
using i64 = long long;
using ll = long long;
#define pb emplace_back
#define X first
#define Y second
#define AI(i) begin(i), end(i)
template<class T> bool chmax(T &a, T b) { return a < b && (a = b, true);}
template<class T> bool chmin(T &a, T b) { return b < a && (a = b, true);}
#ifdef KEV
#define DE(args...) kout("[ " + string(#args) + " ] = ", args)
void kout() { cerr << endl; }
template<class T, class ...U> void kout(T a, U ...b) { cerr << a << ' ', kout(b...); }
template<class T> void debug(T l, T r) { while (l != r) cerr << *l++ << " \n"[l==r]; }
#else
#define DE(...) 0
#define debug(...) 0
#endif

const int MAX_N = 300010, MAX_K = 40;

ll add_v[MAX_K], add_w[MAX_K];

// [ l, r, value ]
// small comes out

set< tuple<ll,ll,ll> > pq[MAX_K];
//priority_queue< tuple<ll,ll,ll>, vector<tuple<ll,ll,ll>>, greater<>> > pq[MAX_K];

int safe_lg(ll v) {
	return v == 0 ? -1 : __lg(v);
}
ll res;
void put(ll l, ll r, ll v) {
	chmax(res, v); 
	chmax(l, 1ll);
	if (l > r) return;
	int k = safe_lg(l); 
	assert(k == safe_lg(r));

	ll nl = l - add_w[k], nr = r - add_w[k], nv = v - add_v[k];
	{
		auto it = pq[k].lower_bound({nl, -1, -1});
		if (it != end(pq[k])) {
			auto [pl, pr, pv] = *it;
			if (nr >= pl) {
				if (nv >= pv) {
					pq[k].erase(it);
					if (pr > nr)
						pq[k].insert({pr+1, nr, pv});
				} else {
					nr = pl-1;
				}
			}

		}
	}
	{
		auto it = pq[k].lower_bound({nl, -1, -1});
		if (it != begin(pq[k])) {
			--it;
			auto [pl, pr, pv] = *it;
			if (nl <= pr) {
				if (nv >= pv) {
					pq[k].erase(it);
					if (pl < nl)
						pq[k].insert({pl, nl-1, pv});
				} else {
					nl = pr+1;
				}
			}
		}
	}

	if (nl <= nr)
		pq[k].insert({nl, nr, nv});
}
void chk(int k) {
	//DE(k);
	while (pq[k].size()) {
		auto [_l, _r, _v] = *pq[k].begin();
		ll l = _l + add_w[k], r = _r + add_w[k], v = _v + add_v[k];
		if (l >= (1ll << k)) break; 
		//DE(l, r, 1ll << k);
		pq[k].erase(pq[k].begin());
		if (l == 0) {
			chmax(res, v);
			if (r > l)
				pq[k].insert({_l+1, _r, _v});
			continue;
		}
		int nk = safe_lg(l);
		ll nr = min(r, (2ll << nk)-1);
		//DE(nr);
		put(l, nr, v);
		if (nr < r) {
			assert(nr+1-add_w[k] <= _r);
			pq[k].insert({nr+1 - add_w[k], _r, _v});
		}
	}
}
void obo(int k, ll dv, ll more) {
	//DE("obo");
	while (pq[k].size()) {
		auto [_l, _r, _v] = *pq[k].rbegin();
		//DE(_l, _r, _v);
		ll l = _l + add_w[k], r = _r + add_w[k], v = _v + add_v[k];
		if (r < dv) break;
		pq[k].erase(prev(end(pq[k])));

		if (r == dv) {
			chmax(res, more + v);
			if (r > l)
				pq[k].insert({_l, _r-1, _v});
			continue;
		}
		int nk = safe_lg(r - dv);
		ll nr = r - dv;
		ll nl = max(l - dv, 1ll << nk);
		put(nl, nr, v + more);
		DE(l, r, v, dv, nl, nr);
		if (nl != l - dv) {
			
			pq[k].insert({_l, nl+dv-1 - add_w[k], _v});
			DE(_l, nl+dv-1 - add_w[k]);
			//DE(_l, nl-1-add_w[k]);
			assert(_l <= nl+dv-1-add_w[k]);
		}
	} 
}

void dd() {
	DE("DD--------------__");
	for (int i = 0;i < MAX_K;++i) if (pq[i].size()) {
		DE(i);
		for (auto [_l, _r, _v] : pq[i]) {
			DE(_l+add_w[i], _r+add_w[i], _v+add_v[i]);
		}
	}
}

int main() {
	ios_base::sync_with_stdio(0), cin.tie(0);
	int N;
	ll T;
	cin >> N >> T;
	vector<ll> w(N), v(N);
	for (auto &i : w) cin >> i;
	for (auto &i : v) cin >> i;
	for (int i = 0;;++i) {
		ll l = 1ll << i, r = min(T, (1ll<<(i+1))-1);
		put(l, r, 0);
		if (r == T) break;
	}
	for (int i = 0;i < N;++i) {
		DE(w[i], v[i]);
		int k = safe_lg(w[i]);
		obo(k, w[i], v[i]);
		for (++k; k < MAX_K;++k) {
			add_v[k] += v[i];
			add_w[k] += -w[i];
			chk(k);
		}
		dd();
	}

	for (int k = 0;k < MAX_K;++k) {
		//DE(k);
		for (auto [_1, _2, _v] : pq[k])
			chmax(res, _v + add_v[k]);
	}
	cout << res << '\n';

}