from itertools import pairwise

safe = 0

def safetycheck(report):
    for i, j in pairwise(report):
        global diffCheck
        diff = abs(int(j)-int(i))
        if diff > 3 or diff < 1:
            diffCheck = 0
        if int(j) > int(i):
            ascDesc.append(1)
        elif int(j) < int(i):
            ascDesc.append(0)

with open('24-2.txt', 'r') as input:
    locReport = input.read().splitlines()
    for n in locReport:
        reportList = n.split(" ")
        diffCheck = 1
        ascDesc = []
        safetycheck(reportList)
        ascCheck = len(set(ascDesc))
        if diffCheck == 1 and ascCheck == 1:
            safe = safe + 1
        else:
            for index,k in enumerate(reportList):
                diffCheck = 1
                ascDesc = []
                elem = reportList.pop(index)
                safetycheck(reportList)
                reportList.insert(index,elem)
                ascCheck = len(set(ascDesc))
                if diffCheck == 1 and ascCheck == 1:
                    safe = safe + 1
                    break

print(safe)