#include "bits/stdc++.h"
using namespace std;

#define int long long
#define fr first
#define sc second
#define eb emplace_back
const char nl = '\n';

void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");} 
 
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define dbg(x...) cerr << "LINE(" << __LINE__ << ") -> " <<"[" << #x << "] = ["; _print(x)
#else
#define dbg(x...)
#endif

signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0);

    int n, k; cin >> n >> k;
    /* int r[n + 1][k + 1], u[n + 1][k + 1]; */
    /* for(int i = 1; i <= n; ++i) { */
    /*     for(int j = 1; j <= k; ++j) { */
    /*         cin >> r[i][j]; */
    /*     } */
    /* } */
    /* for(int i = 1; i <= n; ++i) { */
    /*     for(int j = 1; j <= k; ++j) { */
    /*         cin >> u[i][j]; */
    /*     } */
    /* } */

    /* int p[k + 1] = {}; */
    /* for(int i = 1; i <= k; ++i) { */
    /*     if(r[1][i] > p[i]) { */
    /*         cout << 0; */
    /*         return 0; */
    /*     } */
    /* } */
    /* cout << 1; */
    pair<int, int> mod[n + 1];
    for(int i = 1; i <= n; ++i) cin >> mod[i].fr;
    for(int i = 1; i <= n; ++i) cin >> mod[i].sc;
    sort(mod + 1, mod + n + 1);
    /* for(int i = 1; i<= n; ++i) { */
    /*     cout << mod[i].fr << ' ' << mod[i].sc << nl; */
    /* } */
    /* cout << nl; */
    int p = 0;
    for(int i = 1; i <= n; ++i) {
        if(p < mod[i].fr) {
            cout << i - 1;
            return 0;
        }
        p += mod[i].sc;
    }
    cout << n;
    return 0;
}