#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define sz(x) (int)x.size()
#define all(x) x.begin() , x.end()
const int inf = 1e9 + 7;
struct Dinic {
struct Edge {
int to, rev;
ll c, oc;
ll flow() { return max(oc - c, 0LL); }
};
vector<int> lvl, ptr, q;
vector<vector<Edge>> adj;
Dinic(int n) : lvl(n), ptr(n), q(n), adj(n) {}
void addEdge(int a, int b, ll c, ll rcap = 0) {
adj[a].push_back({b, sz(adj[b]), c, c});
adj[b].push_back({a, sz(adj[a]) - 1, rcap, rcap});
}
ll dfs(int v, int t, ll f) {
if (v == t || !f) return f;
for (int& i = ptr[v]; i < sz(adj[v]); i++) {
Edge& e = adj[v][i];
if (lvl[e.to] == lvl[v] + 1)
if (ll p = dfs(e.to, t, min(f, e.c))) {
e.c -= p, adj[e.to][e.rev].c += p;
return p;
}
}
return 0;
}
ll calc(int s, int t) {
ll flow = 0; q[0] = s;
for(int L=0;L<31;L++){
do {
lvl = ptr = vector<int>(sz(q));
int qi = 0, qe = lvl[s] = 1;
while (qi < qe && !lvl[t]) {
int v = q[qi++];
for (Edge e : adj[v])
if (!lvl[e.to] && e.c >> (30 - L))
q[qe++] = e.to, lvl[e.to] = lvl[v] + 1;
}
while (ll p = dfs(s, t, LLONG_MAX)) flow += p;
} while (lvl[t]);
}
return flow;
}
bool leftOfMinCut(int a) { return lvl[a] != 0; }
};
void solve(){
int n,m;
cin >> n >> m;
pair<int,int>arr[m];// time konum
for(int i = 0;i<m;i++)cin >> arr[i].first;
for(int i = 0;i<m;i++)cin >> arr[i].second;
sort(arr , arr + m);
Dinic dinic(2*n+2);
for(int i = 0;i<m;i++){
for(int j = i+1;j<m;j++){
if(abs(arr[i].second - arr[j].second) <= abs(arr[i].first - arr[j].first)){
dinic.addEdge(i,j+n,1);
}
}
}
for(int i = 0;i<n;i++){
dinic.addEdge(2*n,i,1);
dinic.addEdge(i+n,2*n+1,1);
}
cout << dinic.calc(2*n,2*n+1) << endl;
}
signed main(){
ios_base::sync_with_stdio(0);cin.tie(0);
int testcase=1;//cin >> testcase;
while(testcase--)solve();
cerr << 1000.0 * clock() / CLOCKS_PER_SEC << " ms" << endl;
}
