#include<bits/stdc++.h>
using namespace std;

int i,n,rs;
long long a[100005],b[100005];
map<long long,int> M;

int main()
{
  ios_base::sync_with_stdio(0); cin.tie(0);

  cin>>n;
  for(i=1;i<=n;++i) cin>>a[i],a[i]+=a[i-1];
  for(i=1;i<=n;++i) cin>>b[i],b[i]+=b[i-1];

  M[0]=0;

  for(i=1;i<=n;++i)
  {
    if(M.count(a[i]-b[i])) rs=max(rs,i-M[a[i]-b[i]]);
    else M[a[i]-b[i]]=i;
  }

  cout<<rs<<'\n';

 return 0;
}