#include<stdio.h>
  
void leap_year(int start_year, int end_year);
  
int main(void)
{
    int start_year;
    int end_year;
    int i = 0;
    while(1) {
        scanf("%d %d", &start_year, &end_year);
        if (start_year == 0 && end_year == 0) {
            break;
        } else {
            if ( i == 1) {
                printf("\n");
            }
            leap_year(start_year, end_year);
            i = 1;
        }
    }
    return 0;
}
  
void leap_year(int start_year, int end_year)
{
    int n = 0;
    for (int year = start_year; year <= end_year; year++) {
        if (year % 400 == 0 || (year % 100 != 0 && year % 4 == 0)) {
            printf("%d\n", year);
            n++;
        }
    }
    if (n == 0) {
        printf("NA\n");
    }
}