# 1435 Mmm......

n=int(input())
integers=list(map(int,input().split()))

result=0
for l in range(n-1):
    minNum0=integers[l]
    minNum1=2*1e5+1
    maxNum=integers[l]

    r=l+1
    while r<n:
        if integers[r]<minNum0:
            minNum1=minNum0
            minNum0=integers[r]
        elif integers[r]<minNum1:
            minNum1=integers[r]
        if integers[r]>maxNum:
            maxNum=integers[r]
        if maxNum>minNum0+minNum1:
            break
        result+=1
        r+=1        

print(result)