from sys import stdin, stdout

input = stdin.readline


def print(x):
    stdout.write(str(x) + "\n")


def main():
    N, K, M = map(int, input().split())
    rooms_raw = list(map(int, input().split()))
    rooms = []

    for i in rooms_raw:
        rooms.append([i, 1])

    left_people = 0
    for i in range(M):
        color, direct = map(int, input().split())

        for j in range(N):
            if rooms[j][0] == color:
                if j + direct > N - 1 or j + direct < 0:
                    left_people += rooms[j][1]
                    rooms[j][1] = 0
                else:
                    rooms[j + direct][1] += rooms[j][1]
                    rooms[j][1] = 0
    print(left_people)


def main2():
    N, K, M = map(int, input().split())
    rooms = [int(x) for x in input().split()]

    left_people = 0
    rules=[0]*M
    for i in range(M):
        rules[i]=[int(x) for x in input().split()]

    def kijute(i):
        # az i. emberrel mi tortenik?
        # balra, nem jut ki , jobbra  -1, 0, 1

        for j in range(M):
            if rooms[i] == rules[j][0]:
                i += rules[j][1]
                if i > N - 1:
                    return 1
                elif i < 0:
                    return -1

        return 0

    elso = kijute(0)
    utolso = kijute(N - 1)
    # jobbra:
    lo = 0
    hi = N - 1
    if elso == 1:
        print(N)
        return
    if utolso != 1:
        pass
    else:
        while hi - lo > 1:
            half = (hi + lo) // 2
            if kijute(half) == 1:
                hi = half
            else:
                lo = half
        left_people += N - hi
    # balra:
    lo = 0
    hi = N - 1
    if utolso == -1:
        print(N)
        return
    if elso != -1:
        pass
    else:
        while hi - lo > 1:
            half = (hi + lo) // 2
            if kijute(half) == -1:
                lo = half
            else:
                hi = half
        left_people += hi

    print(left_people)


main2()