#include<iostream>
#include<vector>
using namespace std;
const int N = 1e5+5;
int main(){
int max=0;
int n;
cin>>n;
int i=0,j=0;
vector<int> q;
vector<int> s(N,0);
for(int k = 0 ; k<n; k++){
int t;
cin>>t;
q.push_back(t);
}
while(j<n){
s[q[j]]++;
while(s[q[j]]>1){
s[q[i]]--;
i++;
}
j++;
max = max>(j-i)?max:(j-i);
}
// cout<<i<<" "<<j<<endl;
cout<<max;
return 0;
}