#include <stdio.h>
#include <string.h>

int main(){
    int n, m, len;
    int i, j, flag = 0;
    char str[50][51] = {'\0'};

    scanf("%d %d\n", &n, &m);
    for(i = 0; i < n; i++){
        scanf("%s\n", str[i]);
        for(j = 0; j < m - 3; j++){
            if(strncmp("LOVE", &str[i][j], 4) == 0){
                flag = 1;
                break;
            }
        }
        if(flag == 1)   break;
    }

    if(flag == 1){
        printf("YES\n");
    }else{
        printf("NO\n");
    }

    return 0;
}