#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int N;
    cin >> N;
    vector<ll> T(N), S(N);
    rep(i,N) cin >> T[i];
    rep(i,N) cin >> S[i];

    int count = 0;
    ll cur = 0;
    rep(i,N) {
        if (cur <= S[i]) {
            count++;
            cur = T[i]+S[i];
        }
    }
    cout << count << endl;
}