#include<bits/stdc++.h>
#define int long long
using namespace std;
int read()
{
    int x=0,w=1;
    char ch=0;
    while(ch<'0'||ch>'9')
    {
        if(ch=='-') w=-1;
        ch=getchar();
    }
    while(ch>='0'&&ch<='9')
    {
        x=(x<<1)+(x<<3)+(ch^48);
        ch=getchar();
    }
    return x*w;
}
void write(int x)
{
    if(x<0)
    {
        x=-x;
        putchar('-');
    }
    if(x>=10) write(x/10);
    putchar((x%10)^48);
}
int dp[205][205],a[205],n;
signed main()
{
    freopen("eliminate.in","r",stdin);
    freopen("eliminate.out","w",stdout);
    n=read();
    for(int i=1;i<=n;i++) a[i]=read(),dp[i][i]=1;
    for(int d=2;d<=n;d++)
    {
        for(int i=1;i<=n-d+1;i++)
        {
            int j=i+d-1;
            bool flg=1;
            for(int k=i;k<j;k++)
            {
                if(a[k]!=a[k+1]){flg=0;break;}
            }
            if(flg) dp[i][j]=d*d;
            for(int k=i;k<j;k++) dp[i][j]=max(dp[i][j],dp[i][k]+dp[k+1][j]);
        }
    }
    write(dp[1][n]);
    fclose(stdin);
    fclose(stdout);
    return 0;
}