count = 0
with open("input.txt", "r") as f:
    for line in f.readlines():
        line = line.strip("\n")
        # Some python magic to split out the strings and convert them to integers
        pair = [x.split("-") for x in line.split(",")]
        pair = [[int(y) for y in x] for x in pair]
        if ((pair[0][0] <= pair[1][0] and pair[0][1] >= pair[1][1]) or 
            (pair[1][0] <= pair[0][0] and pair[1][1] >= pair[0][1])):
            count += 1
print(count)