import sys

def bad_level(report):
    delta = None
    prev = None
    safe = True
    for i in range(len(report)):
        n = report[i]
        if prev:
            d2 = n - prev
            if not delta:
                delta = d2
            if abs(d2) > 3 or d2 == 0 or (delta and delta * d2 < 0):
                return i
        prev = n
    return -1

total = 0
for l in sys.stdin:
    report = [int(x) for x in l.split()]
    t = total

    bad = bad_level(report)
    if bad == -1:
        total += 1
    else:
        # it could be that the bad index is any of:
        #  - the result returned by bad_level (1 10 2 3) -- bad causes spike
        #  - the index before that (bad - 1)  (10 1 2 3) -- prev bad causes spike
        #  - the index before that (bad - 2)  (1  2 1 0) -- sign change
        for i in [0, 1, 2]:
            if bad - i >= 0:
                subrep = [report[j] for j in range(len(report)) if j != bad - i]
                if bad_level(subrep) == -1:
                    total += 1
                    break

print(total)