#define _USE_MATH_DEFINES
#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <math.h>
#include <cmath>
#include <stack>
#include <map>
#include <set>
#include <numeric>
#include <iomanip>
#include <climits>
#include <functional>
#include <cassert>
#include <tuple>
using namespace std;
using ll = long long;

int N;
ll H;
ll A[200009], B[200009], S[200009];

int main() {

    cin >> N >> H;
    for(int i = 1; i <= N; ++i) cin >> A[i];
    for(int i = 1; i <= N; ++i) cin >> B[i];
    for(int i = 1; i <= N; ++i) S[i] = S[i-1]+B[i];

    int r = 1;
    ll ans = 0, sum = 0, hi = 0;
    for(int l = 1; l <= N; ++l) {
        r = max(r,l);
        while(r <= N && hi+B[r]*(r-l+1) <= H) {
            sum += A[r];
            hi += B[r]*(r-l+1);
            r++;
        }
        // cout << "l,r,sum:" << l << "," << r << endl;
        // cout << "sum,hi:" << sum << "," << hi << endl;
        ans = max(ans,sum);
        if(r > l) {
            hi -= S[r-1]-S[l-1];
            sum -= A[l];
        }
    }

    cout << ans << endl;

}