h, w = map(int, input().split())
grid = [input().strip() for _ in range(h)]

all_ones = True
count_zeros = 0

for row in grid:
    if '0' in row:
        all_ones = False
    count_zeros += row.count('0')

if all_ones:
    if (h * w) % 2 == 0:
        print("NO")
    else:
        print("YES")
else:
    if count_zeros % 2 == 0:
        print("YES")
    else:
        print("NO")