```python
n = int(input())
lst = list(map(int,input().split()))
lst.sort()
cnt = 0
for i in range(2,len(lst)):
flag = False
for j in range(i-1):
for k in range(j+1, i):
if lst[j] + lst[k] == lst[i]:
cnt += 1
flag = True
break
if flag:
break
print(cnt)
```
by Winds_Land @ 2024-01-28 21:12:17