# -*- coding: utf-8 -*-
import re
def inpl(): return map(int, input().split())

N, M = inpl()
prog = re.compile("LOVE")
S = []

for _ in range(N):
    S.append(input())

for i in range(N):
    if "LOVE" in S[i]:
        print("YES")
        break
else:
    print("NO")