#include <bits/stdc++.h>

using namespace std;

const int MAX_N = 1e5 + 10;

typedef long long LL;

LL a[MAX_N];
LL b[MAX_N];

int n;

map<LL, int> H;

int main() {
  scanf("%d", &n);
  for(int i = 1; i <= n; ++i) {
    scanf("%lld", a + i);
    a[i] += a[i - 1];
  }

  for(int i = 1; i <= n; ++i) {
    scanf("%lld", b + i);
    b[i] += b[i - 1];
  }

  H[0] = 0;

  int sol = 0;

  for(int i = 1; i <= n; ++i) {
    LL now = a[i] - b[i];
    const int R = i;

    if(H.count(now)) {
      const int L = H[now];
      const int dif = R - L;
      if(dif > sol)
        sol = dif;
    } else {
      H[now] = R;
    }
  }

  cout << sol << "\n";

  return 0;
}