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

    mask0 = [0] * (N + 1)  # 1-based indexing
    mask1 = [0] * (N + 1)

    for m in range(M):
        s = input[ptr]
        ptr += 1
        reversed_s = s[::-1]
        for i in range(1, N + 1):
            c = reversed_s[i - 1]
            if c == '0':
                mask0[i] |= (1 << m)
            else:
                mask1[i] |= (1 << m)

    all_ok = True
    for i in range(1, N + 1):
        for j in range(i + 1, N + 1):
            if (mask0[i] & mask1[j]) != 0 or (mask1[i] & mask0[j]) != 0:
                continue
            else:
                all_ok = False
                break
        if not all_ok:
            break

    print("Yes" if all_ok else "No")

if __name__ == "__main__":
    main()