num=int(input())
pos=list(map(int,input().split()))
if(pos.count(0)):
print(len(set(pos))-1)
else:
print(len(set(pos)))
1711D - Rain | 534A - Exam |
1472A - Cards for Friends | 315A - Sereja and Bottles |
1697C - awoo's Favorite Problem | 165A - Supercentral Point |
1493A - Anti-knapsack | 1493B - Planet Lapituletti |
747B - Mammoth's Genome Decoding | 1591C - Minimize Distance |
1182B - Plus from Picture | 1674B - Dictionary |
1426C - Increase and Copy | 520C - DNA Alignment |
767A - Snacktower | 1365A - Matrix Game |
714B - Filya and Homework | 31A - Worms Evolution |
1691A - Beat The Odds | 433B - Kuriyama Mirai's Stones |
892A - Greed | 32A - Reconnaissance |
1236D - Alice and the Doll | 1207B - Square Filling |
1676D - X-Sum | 1679A - AvtoBus |
1549A - Gregor and Cryptography | 918C - The Monster |
4B - Before an Exam | 545B - Equidistant String |