#include <bits/stdc++.h>
using i64 = long long;
constexpr i64 inf = 1ll << 60;
using F = std::pair<i64, int>;
F op(F a, F b) {
return std::min(a, b);
}
F e() {
return {inf, 0};
}
struct SegTree {
int n, size;
std::vector<F> data;
SegTree(const std::vector<F> &vec) : n(vec.size()) {
size = 1;
while (size < n) size *= 2;
data.assign(2 * size, e());
std::copy(vec.begin(), vec.end(), data.begin() + size);
for (int i = size - 1; i >= 1; --i) data[i] = op(data[2 * i], data[2 * i + 1]);
}
void set(int i, const F &v) {
i += size;
data[i] = v;
while (i != 1) {
i /= 2;
data[i] = op(data[2 * i], data[2 * i + 1]);
}
}
F fold(int l, int r) {
l += size;
r += size;
F ret = e();
while (l < r) {
if (l & 1) ret = op(ret, data[l++]);
if (r & 1) ret = op(ret, data[--r]);
l /= 2;
r /= 2;
}
return ret;
}
};
void solve() {
i64 N;
int M;
std::cin >> N >> M;
std::vector<i64> T(M), A(M);
for (auto &e : T) std::cin >> e;
for (auto &e : A) std::cin >> e;
std::vector<std::pair<i64, i64>> points(M);
for (int i = 0; i < M; ++i) {
points[i] = {T[i] + A[i], A[i] - T[i]};
}
std::sort(points.begin(), points.end());
std::vector<std::pair<i64, int>> initVec(M);
for (int i = 0; i < M; ++i) {
initVec[i] = {points[i].second, i};
}
SegTree seg(initVec);
int answer = 0;
while (seg.fold(0, M) != e()) {
++answer;
int l = 0;
while (true) {
const auto mn = seg.fold(l, M);
if (mn.first == inf) break;
seg.set(mn.second, e());
l = mn.second;
}
}
std::cout << answer << std::endl;
}
int main() {
int T;
// std::cin >> T;
T = 1;
while (T--) {
solve();
}
}
