#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
const int N = 2000010, MOD = 1e9 + 7, INF = 0x3f3f3f3f;
int n, m, w[N];

int s[N], t[N];
void solve() {
    scanf("%d", &n);
    for (int i = 1; i < n + 1; i++) scanf("%d", t + i);
    for (int i = 1; i < n + 1; i++) scanf("%d", s + i);
    ll r = 0, res = 0;
    for (int i = 1; i < n + 1; i++) {
       if (s[i] >= r) r = s[i] + t[i], res++;
    }
    printf("%lld\n", res);
}

int main() {
    int T = 1;
    // cin >> T;
    while (T--) solve();
    return 0;
}