f = open("file");
s = f.read();
f.close();
menfou = 0;
for pair in s.splitlines():
    elfs = pair.split(",");
    values = elfs[0].split("-")
    start1 = int(values[0]);
    end1 = int(values[1]);
    values = elfs[1].split("-")
    start2 = int(values[0]);
    end2 = int(values[1]);
    verif = 0;
    for i in range(start1, end1 + 1):
        for y in range(start2, end2 + 1):
            if (y == i):
                verif = 1;
    menfou += verif;
print(menfou);