#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, e) for (int i = (int)(s); i < (int)(e); ++i)

int main() {
	cin.tie(nullptr);
	ios_base::sync_with_stdio(false);
	
	int N;
	cin >> N;
	vector<ll> T(N), S(N);
	rep(i, 0, N) cin >> T[i];
	rep(i, 0, N) cin >> S[i];
	
	ll t = 0;
	int ans = 0;
	rep(i, 0, N) {
		if (t <= S[i]) {
			++ans;
			t = S[i] + T[i];
		}
	}
	cout << ans << '\n';
}