ソースコード
#include<bits/stdc++.h>
using namespace std;
long long int N, A, mod[3][100100]={}, ans, countt[3]={}, mi;
int main(){
cin>>N;
for(int i = 1; i<= N; i++){cin>>A; mod[A%3][countt[A%3]++]=A;}
sort(mod[0],mod[0]+100010, greater<long long>());
sort(mod[1],mod[1]+100010, greater<long long>());
sort(mod[2],mod[2]+100010, greater<long long>());
mi = min(countt[1],countt[2]);
for(int i = 0; i <= N; i++){
ans += mod[0][i];
if(i < mi)ans += mod[1][i]+mod[2][i];
}
if(!ans)ans=-1;
cout<<ans<<endl;
return 0;
}