import sys

def main():
    n = int(sys.stdin.readline())
    m = int(sys.stdin.readline())
    has_zero = [False] * n
    has_one = [False] * n
    for _ in range(m):
        s = sys.stdin.readline().strip()
        for i in range(n):
            c = s[-(i+1)]  # Rightmost is position 1 (0-based from end)
            if c == '0':
                has_zero[i] = True
            else:
                has_one[i] = True
    
    # Check all pairs i < j
    for i in range(n):
        for j in range(i + 1, n):
            # Condition 1: Either i or j has both 0 and 1
            cond1 = (has_zero[i] and has_one[i]) or (has_zero[j] and has_one[j])
            if cond1:
                continue
            # Condition 2: i and j have different bit sets (one is all 0, the other all 1)
            # Check if both are either all 0 or all 1, and they are different
            i_all_single = (has_zero[i] ^ has_one[i])  # Either all 0 or all 1
            j_all_single = (has_zero[j] ^ has_one[j])
            if i_all_single and j_all_single and (has_zero[i] != has_zero[j]):
                continue
            # If neither condition is met, answer is No
            print("No")
            return
    print("Yes")

if __name__ == "__main__":
    main()