#include <iostream>
#define NMAX 100005
#define MMAX 2147483649
#define CMAX 4294967298
#define PRIM 606969
using namespace std;

long a[PRIM], b[NMAX];

int main ()
{
	int n;
	cin >> n;
	for (int i = 1; i <= n; ++i){
		cin >> b[i];
	}
	long x;
	for (int i = 1; i <= n; ++i){
		cin >> x;
		b[i] = b[i-1] + b[i] - x;
		if (a[(b[i]%PRIM+PRIM)%PRIM] == 0){
			a[(b[i]%PRIM+PRIM)%PRIM] = i;
		}
	}
	int maxm = 0;
	for (int i = n; i >= 1; --i){
		if (b[i] == 0){
			maxm = i;
			break;
		}
		else
		if (i - a[(b[i]%PRIM+PRIM)%PRIM] > maxm) {
			maxm = i - a[(b[i]%PRIM+PRIM)%PRIM];
		}
		if (maxm >= i - 1){
			break;
		}
	}
	cout << maxm;
	
	return 0;
}