N = int(input())
L = list(map(int, input().split()))
L.sort(reverse=True)
total = 0

for i in range(N-2):
    a = L[i]
    for j in range(i+1, N-1):
        b = L[j]
        # j以降の項で、初めてL[k] < a-bとなるkを二分探索する
        if L[-1] > a - b:  # 一番最後の項でもOKな場合(j+1以降全部OK)
            total += N - j - 1
        elif L[j+1] <= a - b:  # 一番最初の項からNGな場合
            continue
        else:
            head = j+1  # head はL[head] > a - bを満たす(OK側)
            tail = N-1  # tail はL[tail] <= a - bを満たす(NG側)
            while head+1 != tail:
                if L[(head + tail)//2] > a - b:  # 中間地点はOK側
                    head = (head + tail) // 2
                else:  # 中間地点はNG側
                    tail = (head + tail) // 2
            total += head - j

print(total) N = int(input()) N int(input()) int input() input L = list(map(int, input().split())) L list(map(int, input().split())) list map(int, input().split()) map int input().split() ().split () input split L.sort(reverse=True) L.sort L sort reverse=True reverse True total = 0 total 0 for i in range(N-2):
    a = L[i]
    for j in range(i+1, N-1):
        b = L[j]
        # j以降の項で、初めてL[k] < a-bとなるkを二分探索する
        if L[-1] > a - b:  # 一番最後の項でもOKな場合(j+1以降全部OK)
            total += N - j - 1
        elif L[j+1] <= a - b:  # 一番最初の項からNGな場合
            continue
        else:
            head = j+1  # head はL[head] > a - bを満たす(OK側)
            tail = N-1  # tail はL[tail] <= a - bを満たす(NG側)
            while head+1 != tail:
                if L[(head + tail)//2] > a - b:  # 中間地点はOK側
                    head = (head + tail) // 2
                else:  # 中間地点はNG側
                    tail = (head + tail) // 2
            total += head - j i range(N-2) range N-2 N 2 a = L[i] a L[i] L i for j in range(i+1, N-1):
        b = L[j]
        # j以降の項で、初めてL[k] < a-bとなるkを二分探索する
        if L[-1] > a - b:  # 一番最後の項でもOKな場合(j+1以降全部OK)
            total += N - j - 1
        elif L[j+1] <= a - b:  # 一番最初の項からNGな場合
            continue
        else:
            head = j+1  # head はL[head] > a - bを満たす(OK側)
            tail = N-1  # tail はL[tail] <= a - bを満たす(NG側)
            while head+1 != tail:
                if L[(head + tail)//2] > a - b:  # 中間地点はOK側
                    head = (head + tail) // 2
                else:  # 中間地点はNG側
                    tail = (head + tail) // 2
            total += head - j j range(i+1, N-1) range i+1 i 1 N-1 N 1 b = L[j] b L[j] L j if L[-1] > a - b:  # 一番最後の項でもOKな場合(j+1以降全部OK)
            total += N - j - 1
        elif L[j+1] <= a - b:  # 一番最初の項からNGな場合
            continue
        else:
            head = j+1  # head はL[head] > a - bを満たす(OK側)
            tail = N-1  # tail はL[tail] <= a - bを満たす(NG側)
            while head+1 != tail:
                if L[(head + tail)//2] > a - b:  # 中間地点はOK側
                    head = (head + tail) // 2
                else:  # 中間地点はNG側
                    tail = (head + tail) // 2
            total += head - j L[-1] > a - b L[-1] L -1 a - b a b total += N - j - 1 total N - j - 1 N - j N j 1 elif L[j+1] <= a - b:  # 一番最初の項からNGな場合
            continue
         L[j+1] <= a - b L[j+1] L j+1 j 1 a - b a b continue head = j+1 head j+1 j 1 tail = N-1 tail N-1 N 1 while head+1 != tail:
                if L[(head + tail)//2] > a - b:  # 中間地点はOK側
                    head = (head + tail) // 2
                else:  # 中間地点はNG側
                    tail = (head + tail) // 2
             head+1 != tail head+1 head 1 tail if L[(head + tail)//2] > a - b:  # 中間地点はOK側
                    head = (head + tail) // 2
                else:  # 中間地点はNG側
                    tail = (head + tail) // 2
             L[(head + tail)//2] > a - b L[(head + tail)//2] L (head + tail)//2 head + tail head tail 2 a - b a b head = (head + tail) // 2 head (head + tail) // 2 head + tail head tail 2 tail = (head + tail) // 2 tail (head + tail) // 2 head + tail head tail 2 total += head - j total head - j head j print(total) print total total += head - j head - j total tail = (head + tail) // 2 (head + tail) // 2 tail head = (head + tail) // 2 (head + tail) // 2 head N = int(input()) int(input()) N total += N - j - 1 N - j - 1 total tail = N-1 N-1 tail head = j+1 j+1 head a = L[i] L[i] a b = L[j] L[j] b L = list(map(int, input().split())) list(map(int, input().split())) L total = 0 0 total
N = int(input())
L = list(map(int, input().split()))
L.sort(reverse=True)
total = 0

for i in range(N-2):
    a = L[i]
    for j in range(i+1, N-1):
        b = L[j]
        # j以降の項で、初めてL[k] < a-bとなるkを二分探索する
        if L[-1] > a - b:  # 一番最後の項でもOKな場合(j+1以降全部OK)
            total += N - j - 1
        elif L[j+1] <= a - b:  # 一番最初の項からNGな場合
            continue
        else:
            head = j+1  # head はL[head] > a - bを満たす(OK側)
            tail = N-1  # tail はL[tail] <= a - bを満たす(NG側)
            while head+1 != tail:
                if L[(head + tail)//2] > a - b:  # 中間地点はOK側
                    head = (head + tail) // 2
                else:  # 中間地点はNG側
                    tail = (head + tail) // 2
            total += head - j

print(total)
