#include<iostream>
using namespace std;
long long a[1000005],b[1000005];
int main()
{
    long long n,s,t=0;
    cin>>n>>s;
    for (long long i=0;i<n;i++)
    {
        cin>>a[i];
    }
    for (long long i=0;i<n;i++)
    {
        cin>>b[i];
    }
    for (long long i=0;i<n;i++)
    {
        if (s>=a[i])
        {
            s+=b[i];
            t++;
        }
        else
        {
            cout<<t<<endl;
            return 0;
        }
    }
    cout<<t<<endl;
    return 0;
}