import sys

def main():
    input = sys.stdin.read
    data = input().split()
    idx = 0
    N = int(data[idx])
    idx += 1
    M = int(data[idx])
    idx += 1
    
    max_post = -1
    max_dest = -1
    
    for _ in range(M):
        x = int(data[idx])
        idx += 1
        d = int(data[idx])
        idx += 1
        if x > max_post:
            max_post = x
        for __ in range(d):
            y = int(data[idx])
            idx += 1
            if y > max_dest:
                max_dest = y
                
    print(max_post + max_dest)

if __name__ == '__main__':
    main()