count = 0
with open("input.txt", "r") as f:
    for line in f.readlines():
        line = line.strip("\n")
        # "A-B,C-D"
        twoelves = line.split(",")
        # ["A-B", "C-D"]

        # "A-B"
        leftelf = twoelves[0].split("-")
        # ["A", "B"]
        lb1 = int(leftelf[0])
        ub1 = int(leftelf[1])

        # "C-D"
        rightelf = twoelves[1].split("-")
        # ["C", "D"]
        lb2 = int(rightelf[0])
        ub2 = int(rightelf[1])

        if ((lb1 <= lb2 and ub1 >= ub2) or # Elf 1 fully covers elf 2
            (lb2 <= lb1 and ub2 >= ub1)): # Elf 2 fully covers elf 1
            count += 1
print(count)