#include <bits/stdc++.h>
#define int ll
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define rng(i,c,n) for(int i=c;i<n;i++)
#define fi first
#define se second
#define pb push_back
#define all(a) a.begin(), a.end()
#define sz(a) ((int) a.size())
#define vec(...) vector<__VA_ARGS__>
#define _4ab8goq ios::sync_with_stdio(0),cin.tie(0);
typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> pii;
void print(){cout<<'\n';}
template<class h,class...t>
void print(const h&v,const t&...u){cout<<v<<' ',print(u...);}

void slv(){
	int n,h;
	cin>>n>>h;

	vi a(n);
	rep(i,n){
		cin>>a[i];
	}

	vi b(n);
	rep(i,n){
		cin>>b[i];
	}

	vi ps_a;
	rep(i,n){
		ps_a.pb((sz(ps_a)?ps_a.back():0)+a[i]);
	}

	vi ps_bc;
	rep(i,n){
		ps_bc.pb((sz(ps_bc)?ps_bc.back():0)+i*b[i]);
	}

	vi ps_b;
	rep(i,n){
		ps_b.pb((sz(ps_b)?ps_b.back():0)+b[i]);
	}

	auto range_sum=[&](vi&ps,int l,int r)->int{
		return ps[r]-(!l?0:ps[l-1]);
	};

	int ans=0;
	rep(i,n){
		int l=0,r=i;
		int opt=-1;
		while(l<=r){
			int m=(l+r)/2;
			int now=range_sum(ps_bc,m,i);
			now-=(m-1)*range_sum(ps_b,m,i);
			if(now<=h){
				opt=m,r=m-1;
			}else{
				l=m+1;
			}
		}
		if(opt!=-1){
			ans=max(ans,range_sum(ps_a,opt,i));
		}
	}
	cout<<ans<<"\n";
}

signed main(){
_4ab8goq;
	slv();
}