class FenwickTreeMax:
    def __init__(self, size):
        self.size = size
        self.tree = [0] * (size + 2)  # 1-based indexing, size up to M (10^3)

    def update(self, index, value):
        while index <= self.size:
            if self.tree[index] < value:
                self.tree[index] = value
            else:
                break  # No need to update further if the value is not larger
            index += index & -index

    def query(self, index):
        res = 0
        while index > 0:
            res = max(res, self.tree[index])
            index -= index & -index
        return res

def main():
    import sys
    input = sys.stdin.read().split()
    ptr = 0
    N = int(input[ptr]); ptr +=1
    M = int(input[ptr]); ptr +=1
    Q = int(input[ptr]); ptr +=1

    pairs = []
    for _ in range(Q):
        a = int(input[ptr]); ptr +=1
        b = int(input[ptr]); ptr +=1
        pairs.append( (a, b) )

    # Sort by x, then y
    pairs.sort(key=lambda x: (x[0], x[1]))

    ft = FenwickTreeMax(M)
    max_answer = 0

    for (x, y) in pairs:
        # Query max up to y-1
        if y == 1:
            max_prev = 0
        else:
            max_prev = ft.query(y-1)
        current = max_prev +1
        # Check current max at y
        current_val = ft.query(y)  # Current maximum up to y
        if current_val < current:
            ft.update(y, current)
        if current > max_answer:
            max_answer = current

    print(max_answer)

if __name__ == "__main__":
    main()