import bisect

def main():
    import sys
    input = sys.stdin.read().split()
    idx = 0
    N = int(input[idx]); idx +=1
    M = int(input[idx]); idx +=1
    Q = int(input[idx]); idx +=1
    
    pairs = []
    for _ in range(Q):
        a = int(input[idx]); idx +=1
        b = int(input[idx]); idx +=1
        pairs.append( (a, b) )
    
    # 按a升序，a相同则b降序排列
    pairs.sort(key=lambda x: (x[0], -x[1]))
    
    bs = [b for a, b in pairs]
    
    # 计算最长严格递增子序列的长度
    tail = []
    for b in bs:
        # 找第一个大于等于b的位置
        pos = bisect.bisect_left(tail, b)
        if pos == len(tail):
            tail.append(b)
        else:
            tail[pos] = b
    print(len(tail))

if __name__ == '__main__':
    main()