ABC369Cmemo

def count_arithmetic_subarrays(A):
    N = len(A)
    if N < 2:
        return N

    # 1. 差分配列 B を作成
    B = [A[i+1] - A[i] for i in range(N-1)]

    # 2. ランレングス圧縮
    f = []
    current_diff = B[0]
    length = 1

    for i in range(1, len(B)):
        if B[i] == current_diff:
            length += 1
        else:
            f.append(length)
            current_diff = B[i]
            length = 1
    f.append(length)

    # 3. 部分列の数を計算
    total_count = 0
    for D_i in f:
        total_count += D_i * (D_i + 1) // 2

    # 4. 各要素単体も等差数列としてカウント
    total_count += N

    return total_count

# 入力
N = int(input("N: "))  # 数列の長さ
A = list(map(int, input("A: ").split()))  # 数列

# 計算
count = count_arithmetic_subarrays(A)

# 出力
print(count)