nm=input()
nm=nm.rstrip().split(" ")
n=int(nm[0])
m=int(nm[1])

count=0
for i in range(n):
    line=input()
    if "LOVE" in line:
        count=count+1
    else:
        i+=1
        
if count>=1:
    print("YES")
else:
    print("NO")