#/usr/bin/env python

import re

RE_MATCH = re.compile(r"^(\d+)\-(\d+),(\d+)\-(\d+)$")

total = 0
with open("input.txt", "r") as f:
    for line in f:
        line = line.strip()
        m = RE_MATCH.match(line)
        
        l1 = set(list(range(int(m.group(1)),int(m.group(2))+1)))
        l2 = set(list(range(int(m.group(3)),int(m.group(4))+1)))
        l = l2.intersection(l1)
        
        if (l == l1) or (l == l2):
            total += 1
print(total)