#include<iostream>

 #include<cstring>

 using namespace std;

 const int maxn = +;

 int a[maxn];

 int d[maxn][];

 int n,sum;

 int main() {

     ios::sync_with_stdio(false);

     cin>>n;

     for(int i=;i<=n;i++) cin>>a[i] , sum+=a[i];

     memset(d,-,sizeof(d));

     d[][]=;

      for(int i=;i<=n;i++)

         for(int j=;j<=sum;j++)

         {

             if(d[i-][j]>-)

                 d[i][j]=d[i-][j];

             if(a[i]>=j&&d[i-][a[i]-j]>-)

                 d[i][j]=max(d[i][j],d[i-][a[i]-j]+j);

             if(j+a[i]<=sum&&d[i-][j+a[i]]>-)

                 d[i][j]=max(d[i][j],d[i-][j+a[i]]);

             if(j>=a[i]&&d[i-][j-a[i]]>-)

                 d[i][j]=max(d[i][j],d[i-][j-a[i]]+a[i]);

         }

     if(d[n][]<=) cout<<"Impossible";

     else cout<<d[n][];

     return ;

 }