// #pragma GCC optimize("O3,Ofast,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define MP make_pair
#define pb push_back
#define REP(i,n) for(int i = 0; (i) < (n); (i)++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
void fastio() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
}
const double EPS = 0.00001;
const int INF = 1e9+500;
const int N = 3e5+5;
const int ALPH = 26;
const int LGN = 25;
constexpr int MOD = 1e9+7;
int n,m,k;
vector<int> pr;
vector<array<int, 2> > evs;
int mtch(int x) {
for(int i = x + 1; i < m; i++) {
if(pr[i] == -1 && evs[i][0] - evs[x][0] >= abs(evs[i][1] - evs[x][1])) {
pr[i] = x;
return -1;
}
}
for(int i = x + 1; i < m; i++) {
if(evs[i][0] - evs[x][0] >= abs(evs[i][1] - evs[x][1])) {
int tmp = pr[i];
pr[i] = x;
return tmp;
}
}
return -1;
}
inline void solve() {
cin >> n >> m;
evs.resize(m);
pr.assign(m + 3, -1);
for(int i = 0; i < m; i++) {
cin >> evs[i][0];
}
for(int i = 0; i < m; i++) {
cin >> evs[i][1];
}
sort(all(evs));
int ans = 0;
for(int i = 0; i < m; i++) {
if(pr[i] != -1) {
continue;
}
ans++;
int cur = i;
while(1) {
cur = mtch(cur);
if(cur == -1) break;
}
}
cout << ans << "\n";
}
signed main() {
fastio();
int test = 1;
// cin>>test;
while(test--) {
solve();
}
}
