#include <bits/stdc++.h>
using namespace std;
#define endl "\n"
#define int long long
#define pii pair<int, int>
#define ff first
#define ss second
#define entire(x) (x).begin(), (x).end()
int32_t main(){
ios::sync_with_stdio(false); cin.tie(nullptr);
int n, k; cin >> n >> k;
vector<pii> a(n);
for (int i = 0; i < n; i++) cin >> a[i].ff;
for (int i = 0; i < n; i++) cin >> a[i].ss;
sort(entire(a));
// vector<vector<int>> a(n, vector<int>(k, 0)), b(n, vector<int>(k, 0));
// for (int i = 0; i < n; i++) for (int j = 0; j < k; j++) cin >> a[i][j];
// for (int i = 0; i < n; i++) for (int j = 0; j < k; j++) cin >> b[i][j];
int cur = 0, ans = 0;
for (auto [r, u] : a){
if (cur < r) break;
cur += u; ans++;
}
cout << ans << endl;
return 0;
}
