include <bits/stdc++.h>

using namespace std;

int main()
{
int N,t,len=0;
cin>>N;
vector<int> arr(N+1,0);
for(int i=1;i<=N;i++)
{
  cin>>t;
  if(t>0)
arr[i]=arr[i-1]+1;
else if(t<0)
 arr[i]=arr[i-1]-1;
else
arr[i]=arr[i-1];
if(arr[i]==0)
len = max(len,i);
}</int>

for(int i=1;i<=N;i++)
    for(int j=N;j>len+i;j--)
    {
        if(arr[j]==arr[i])
        {
            len =max(len,j-i);
            break;
        }
    }
cout<<len<<endl;
return 0;

}