points = 0

def contains(ran1, ran2):
    return ran1.start <= ran2.start and ran1.stop >= ran2.stop
def overlap(ran1, ran2):
    return ran1.stop >= ran2.start and ran1.start <= ran2.stop

#with open("example") as f:
with open("input") as f:
    lines = f.readlines()
for line in lines:
    r1, r2 = line.strip().split(",")
    r11, r12 = list(map(int, r1.split("-")))
    r21, r22 = list(map(int, r2.split("-")))
    ran1, ran2 = range(r11, r12), range(r21, r22)
    if overlap(ran1, ran2):
        points += 1
print(points)