#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <cassert>
using namespace std;

const int N = 1e5 + 5;
long long a[N];
map<long long, int> mp;

int main() {
  int n;
  cin >> n;
  int ans = 0;
  for(int i = 1; i <= n; ++i)
    scanf("%lld", &a[i]);
  for(int i = 1; i <= n; ++i) {
    long long b;
    scanf("%lld", &b);
    a[i] -= b;
    a[i] += a[i-1];
  }
  ++n;
  for(int i = 0; i < n; ++i) {
    auto it = mp.find(a[i]);
    if(it != mp.end()) {
      ans = max(ans, i - it->second);
    } else {
      mp[a[i]] = i;
    }

  }
  cout << ans << endl;

  return 0;
}