n=int(input()) a=[int(n) for n in input().split(' ')] k=list(set(a)) k=list(sorted(k)) t=0 print(a) print(k) for i in range(len(k)): print(i) if k[i] in a: a.remove(k[i]) if (k[i]-1) in a: a.remove(k[i]-1) if (k[i]+1) in a: a.remove(k[i]+1) t=t+k[i] if(len(a)==0): break print(t)
8 7 2 1 8 3 3 6 6