n = int(input().strip())
s = list(map(int, input().strip().split()))
stack = []
max_lucky = 0
for i in range(n):
while stack and stack[-1] < s[i]:
max_lucky = max(max_lucky, stack[-1] ^ s[i])
stack.pop()
if stack:
max_lucky = max(max_lucky, stack[-1] ^ s[i])
stack.append(s[i])
print(max_lucky)
#include<bits/stdc++.h>
using namespace std;
int n;
int a[1000010];
stack<int> st;
int ans=-1;
int main()
{
cin>>n;
for(int i=1;i<=n;i++) cin>>a[i];
for(int i=1;i<=n;i++)
{
while(st.size()) {
ans=max(ans,a[i]^st.top());
if(a[i]<=st.top())break;
st.pop();
}
st.push(a[i]);
// if(st.size()>=2)
// {
// int t1=st.top();
// st.pop();
// int t2=st.top();
// ans=max(ans,t1^t2);
// cout<<ans<<" ";
// st.push(t1);
// }
}
cout<<ans<<endl;
return 0;
}
1538A - Stone Game | 1454C - Sequence Transformation |
165B - Burning Midnight Oil | 17A - Noldbach problem |
1350A - Orac and Factors | 1373A - Donut Shops |
26A - Almost Prime | 1656E - Equal Tree Sums |
1656B - Subtract Operation | 1656A - Good Pairs |
1367A - Short Substrings | 87A - Trains |
664A - Complicated GCD | 1635D - Infinite Set |
1462A - Favorite Sequence | 1445B - Elimination |
1656C - Make Equal With Mod | 567A - Lineland Mail |
1553A - Digits Sum | 1359B - New Theatre Square |
766A - Mahmoud and Longest Uncommon Subsequence | 701B - Cells Not Under Attack |
702A - Maximum Increase | 1656D - K-good |
1426A - Floor Number | 876A - Trip For Meal |
1326B - Maximums | 1635C - Differential Sorting |
961A - Tetris | 1635B - Avoid Local Maximums |