#include <algorithm>
#include <cstdio>
#include <cstring>

int n;
int a[256];
int A[256], B[256];
int next[256];
int last[256];
int memo[201][201][201];

int rec( int lo, int hi, int cnt ) {
   if( lo > hi ) return 0;

   int &ret = memo[lo][hi][cnt];
   if( ret != -1 ) return ret;

   ret = (cnt+B[lo])*(cnt+B[lo]) + rec( lo+1, hi, 0 );

   for( int i = next[lo]; i <= hi; i = next[i] )
      ret = std::max( ret, rec( lo+1, i-1, 0 ) + rec( i, hi, cnt+B[lo] ) );   

   return ret;
}

int main( void ) {
   int T = 1;
   //   scanf( "%d", &T );
   for( int tt = 1; tt <= T; ++tt ) {
      scanf( "%d", &n );
      int m = 0;
      for( int i = 0; i < n; ++i ) {
         scanf( "%d", &a[i] );
         if( i == 0 || a[i] != a[i-1] ) { 
            ++m; 
            A[m-1] = a[i]; 
            B[m-1] = 1; 
         }
         else ++B[m-1];         
      }
      n = m;

      memset( last, 0x3F, sizeof last );
      for( int i = n-1; i >= 0; --i ) {
         next[i] = last[A[i]];
         last[A[i]] = i;
      }

      memset( memo, -1, sizeof memo );

      printf( "%d\n", rec( 0, n-1, 0 ) );
   }
   return 0;
}