#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
#define pb push_back
#define all(a) a.begin(), a.end()
#define sz(a) ((int)a.size())
const int mod = 998244353, N = 100005;

int n,w[N],v[N];
ll t;

int main() {
    ios::sync_with_stdio(false), cin.tie(0);
    cin >> n >> t;
    vector<pair<ll,ll>> vec;
    vec.pb({t+1,0});
    for(int i=0; i<n; ++i) cin >> w[i];
    for(int i=0; i<n; ++i) cin >> v[i];
    for(int i=0; i<n; ++i){
        vector<pair<ll,ll>> vec2;
        for(auto &[len,x]: vec){
            if(len>w[i]){
                vec2.pb({len-w[i],x+v[i]});
            }
            len=min<ll>(len,w[i]);
        }
        vector<pair<ll,ll>> res;
        auto ins=[&](ll len, ll x){
            //cout << "ins " << i << ' ' << len << ' ' << x << "\n";
            while(sz(res)&&res.back().second<=x) res.pop_back();
            //if(sz(res)&&res.back().second>=x) return;
            //while(sz(res)&&res.back().first==len&&res.back().second<x) res.pop_back();
            res.pb({len,x});
        };
        int cur1=0,cur2=0;
        while(cur1<sz(vec)||cur2<sz(vec2)){
            if(cur1==sz(vec)){
                ins(vec2[cur2].first,vec2[cur2].second);
                cur2++;
            }
            else if(cur2==sz(vec2)){
                ins(vec[cur1].first,vec[cur1].second);
                cur1++;
            }
            else if(vec[cur1].first<vec2[cur2].first){
                ins(vec[cur1].first,vec[cur1].second);
                cur1++;
            }
            else{
                ins(vec2[cur2].first,vec2[cur2].second);
                cur2++;
            }
        }
        vec=res;
        //cout << "vec " << i << ' ' << sz(vec) << "\n";
        //for(auto &[len,x]: vec) cout << len << ' ' << x << "\n";
    }
    cout << vec[0].second << "\n";
}