d, n, m = map(int, raw_input().split())
missing = {int(day): set([]) for day in raw_input().split()}

intervals = []
solved = []

while m:
    start, end = map(int, raw_input().split())
    days = []

    for day in missing:
        if day >= start and day <= end:
            days.append(day)

    intervals.append(days)
    m -= 1

count = 0
intervals = sorted(intervals, key=lambda x: -len(x))
for i in intervals:
    if len(solved) != n:
        use = False
        for l in missing:
            if l not in solved and l in i:
                solved.append(l)
                use = True
        if use:
            count += 1

print count