Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

var sc = bufio.NewScanner(os.Stdin)

//Sliceconvtoi ...
func Sliceconvtoi() []int {
	strs := strings.Split(sc.Text(), " ")

	var ints []int
	var x int

	for _, s := range strs {
		x, _ = strconv.Atoi(s)
		ints = append(ints, x)
	}

	return ints
}

func isLeapYear(y int) bool {
	return (y%4 == 0 && y%100 > 0) || (y%4 == 0 && y%400 == 0)
}

func cntLeap(y []int) {
	cnt := 0

	for i := y[0]; i <= y[1]; i++ {
		if isLeapYear(i) {
			cnt++
			fmt.Println(i)
		}
	}

	if cnt == 0 {
		fmt.Println("NA")
	}
}

func main() {
	num := 0

	for sc.Scan() {
		y := Sliceconvtoi()

		if y[0] == 0 && y[1] == 0 {
			break
		}

		if num > 0 {
			fmt.Println()
		}

		cntLeap(y)
		num++
	}

}

C++: #include <stdio.h>
#include <stdbool.h>

bool is_leap_year(int y);

int get_leap_years(int* a, int b, int c);

int main()
{
    int leap_years_list[1000]; //A.D. 0 - A.D. 3000 の間に閏年は高々1000個しかない

    bool first_set = true; //一つ目のセットの前にだけは改行を入れてはいけないので

    while (true) {
        int year_begin, year_end;

        //読み込み
        scanf("%d %d", &year_begin, &year_end);

        //終了判定
        if (year_begin == 0 && year_end == 0) {
            break;
        }

        //閏年を計算する
        int leap_years_count = get_leap_years(leap_years_list, year_begin, year_end);

        //セットとセットの間には空行を入れる
        if (first_set) {
            first_set = false;
        } else {
            putchar('\n'); //putcharは一文字だけ出力する関数です
        }

        //閏年を出力
        if (leap_years_count == 0) {
            puts("NA"); //putsは与えられた文字列を出力した後改行する関数です
        } else {
            for (int i = 0; i < leap_years_count; i++) {
                printf("%d\n", leap_years_list[i]);
            }
        }
        
    }
}

bool is_leap_year(int y)
{
    if (y % 400 == 0) {
        return true; 
    } else if (y % 100 == 0) {
        return false;
    } else {
        return y % 4 == 0;
    }
}

int get_leap_years(int* a, int b, int c)
{
    int s;
    for (int i = 0; b <= c; ++i) {        
        if (is_leap_year(b) == true) {
        a[i] = b;
        ++s;
        }
        ++b;
    }
    return s;
}

C++: #include <stdio.h>

void Leap_Year(int start_year, int end_year)
{
    if ((start_year != 0) || (end_year != 0)) {
        if (end_year - start_year < 3) {
            if (((start_year % 4) < (end_year % 4)) || ((start_year % 100) > (end_year % 100))) { 
                if ((start_year % 400) < (end_year % 400)) {
                    printf("NA\n");
                } else {
                    printf("%d", start_year + 4 - start_year % 4);
                }
            }
        } else {
            for (int i = start_year; i <= end_year; ++i) {
                if (i % 400 != 0) {
                    if ((i % 100 != 0) && (i % 4 == 0)) {
                        printf("%d\n", i);
                    }
                } else {
                    printf("%d\n", i);
                }
            }
        }
    }
}

int main(void)
{
    int start_year, end_year;
    scanf("%d %d", &start_year, &end_year);
    Leap_Year(start_year, end_year);
    return 0;
}

C++: #include<iostream>
#include<string>
#include<cmath>
#include<cstdio>
#include<queue>
#include<utility>
#include<stack>

using namespace std;





int main(){
	int a;
	int b;
	bool first=true;
	
	while(cin>>a>>b,a*b){
		if(first!=true){
			cout<<endl;
		}else{
			first=false;
		}
		bool j=false;
		for(int i=a;i<b;i++){
			if(i%4==0){
				if(i%400==0){
					j=true;
					cout<<i<<endl;
				}else if(i%100==0){
				}else{
					j=true;
					cout<<i<<endl;
				}
			}else{
			}
		}
		
		if(j==false)cout<<"NA"<<endl;
		
	}
	
	
	
	
	
	return 0;
}

C++: #include <iostream>

int LeapYear (int x);
int main()
{
    int a,b;
    std::cin >> a >> b;
    while (true) {
        int n = 0;
        if (a == 0 && b == 0) {
	        break;
        } else {
            for (int i = a; i <= b; i++) {
                if (LeapYear (i) == 1) {
                    std::cout << i <<std::endl;
                    n++; //kokode "n" ni kasan sareru to sita de NA ga denakunaru
            }				
        }
        if (n == 0) {
            std::cout << "NA" << std::endl;
        }
        std::cin >> a >> b;
        }
    }
    return 0;
}

int LeapYear (int x)
{
    if (x % 400 == 0) {
    return 1;
    } else if (x % 100 == 0) {
    return 0;
    } else if (x % 4 == 0) {
    return 1;
    }else {
    return 0;
    }
}

C++: #include <iostream>


int leap_year(int y) {
	if( y % 400 == 0) {
		return 1;/*???????????´*/
	} else if (y % 100 == 0 && y % 400 != 0) {
		return 0;/*???????????´??§??????*/
	} else if (y % 4 == 0 && y % 100 != 0) {
		return 1;
	} else {
		return 0;
	}
}
int main()
{
	int a;
	int b;
	while (true) {
		std::cin >> a >> b;
		if (a == 0 && b == 0) {
			break;
		} else {
			int sum = 0;
			for (int k = a; k <= b; k++) {
				sum = sum + leap_year(k);
			}
			if (sum == 0 /*????????????????????´?????????*/) {
				std::cout << "NA" << std::endl;
			} else {
			    for (int i =a; i <= b; i++) {
					if (leap_year(i) == 1) {
						std::cout << i << std::endl;
					}
				}
			}
			std::cout << std::endl;
		}
	}
	return 0;
}

C++: #include <iostream>

bool isLY(int y)
{
    if (y%400 == 0) {
        return true;
    } else if (y%100 == 0) {
        return false;
    } else if (y%4 == 0) {
        return true;
    } else {
        return false;
    }
}

int main(){
    int a,b;
    bool noLY;
    while (true) {
        noLY = true;
        std::cin >> a >> b;
        if (a==0 && b==0) {
            break;
        }
        for (int i=0; i <= (b-a); i++) {
            if (isLY(a+i)) {
                std::cout << a+i << std::endl;
                noLY = false;
            }
        }
        if(noLY){
            std::cout << "NA\n";
        }
        std::cout << std::endl;
    }
    return 0;
}

C++: #include <iostream>
#include <stack>
#include <algorithm>
#include <cstdio>
#include <sstream>
#include <string>
#include <vector>
#include <cmath>

#define rep(x,to) for(int x=0;x<to;x++)
#define rep2(x,from,to) for(int x=from;x<to;x++)

using namespace std;


int main(void){

int a,b;
	
	while(cin >> a >> b){
		if(a==0  && b==0 || cin.eof()) break;
		int cnt=0;
		while(1){
			if(a%400 == 0 || a%100 != 0 && a%4 == 0 ){
				cout << a << endl;
				cnt++;
			}
			a++;
			if(a > b) break;
		}	
		if(cnt==0) cout << "NA\n";
//		cout << endl;
	}
	return 0;
	
}

C++: #include <iostream>
#include <stdio.h>
#include <string.h>
#include <string>
#include <algorithm>
using namespace std;

bool uru[3000];

void q93() {
	memset(uru, 0, sizeof(uru));
	for (int i = 0; i < 3000; i += 4) {
		uru[i] = true;
	}
	for (int i = 0; i < 3000; i += 100) {
		uru[i] = false;
	}
	for (int i = 0; i < 3000; i += 400) {
		uru[i] = true;
	}

	int a, b;
	for (; cin >> a >> b;) {
		if (!a) break;
		bool print_flag = false;
		for (int i = a; i < b; i++) {
			if (uru[i]) {
				cout << i << endl;
				print_flag = true;
			}
		}
		if (!print_flag) cout << "NA" << endl;
		cout << endl;
	}
}
int main() {
	q93();
	return 0;
}

C++: #include <stdio.h>

int main(void)
{
    int a, b, y, counter, setcount;
    setcount = 0;
    while(1){
        counter = 0;
        scanf("%d %d", &a, &b);
        setcount++;
        if (a == 0&& b == 0){
            break;
        }
        y = a;
        if (setcount != 1)// print a line at the begining if it != the first set
            {
                printf("\n");
            }
        for (int i = a; i <= b; i++){// y == i
            if (!(y%400)){
                printf("%d\n", y);
                counter++;
            }else if((!(y%4)) && y%100){
                printf("%d\n", y);
                counter++;
            }
            y++;
        }
        if (counter == 0){//detech whether leap year appears
            printf("NA\n");
        }
    }
    return 0;
}