import re

def mainProc(lst):

    for s in lst :
        if re.search('LOVE',s) is not None:
            print('YES')
            break
    else :
        print('NO')

if __name__ == '__main__':
    
    n, m = map(int,input().split())

    lst = []
    for i in range(n) :
        lst.append(input())

    mainProc(lst)