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import sys

n = int(input().strip())
numbers  = list(map(int, input().strip().split(' ')))


def sign(a, b):
    if a == b:
        return 0
    elif a > b:
        return -1
    elif a < b:
        return 1

def compute(numbers, current_sign):
#    print('current sign', current_sign)
    numbers = numbers[:]
    cost = 0
    for i in range(1, len(numbers)):
        prev = numbers[i-1]
        curr = numbers[i]
        s = sign(prev, curr)

        if s == current_sign:
            pass
        else:
            cost += 1
            numbers[i] = current_sign * 1e9

#            print('cost at', i, prev, curr)
 
        current_sign *= -1
    return cost


print(min(compute(numbers, 1), compute(numbers, -1)))