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<iostream>
using namespace std;

int main()
{
    int a,b;

    while(cin >> a >> b , a || b)
    {
        bool NAflag = true;

        for(int i=a; i<=b; i++){
            if(i%4 == 0 && (i%100 != 0 || i%400 == 0)){
                cout << i << endl;
                NAflag = false;
            }
        }
        if(NAflag){
            cout << "NA" << endl;
        }

        cout << '\n';
    }

    return 0;
}

C++: #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");
    }
}

C++: #include <stdio.h>

int main(void)
{
    int a, b, y, counter;
    while(1){
        counter = 0;
        scanf("%d %d", &a, &b);
        if (a == 0&& b == 0){
            break;
        }
        if (b >= 3000 || a < 0){
            printf("NA\n");
        }else{
            y = a;
            //printf("%d\n", a);
            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){
                printf("NA\n");
            }else{
                printf("\n");
            }
        }
    }
    return 0;
}

C++: #include<iostream>
#include<cstdio>
using namespace std;

int main(){
  int a,b,k=0,i,j=0;
  
  while(1){
    cin>>a>>b;
    if(a==0&&b==0)break;
   
    if(j) cout<<endl;
    k=0;
    for(i=a;i<=b;i++){
      if(i%4==0&&i%100!=0){cout<<i<<endl;k++;}
      if(i%400==0){cout<<i<<endl;}
    }    
    if(k==0)cout<<"NA"<<endl;
    j=1;  
  }
return 0;
}

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

bool judge(int year)
{
    bool flag;
    if (year % 400 == 0) {
        flag = true;                
    } else if (year % 100 == 0) {
        flag = false;
    } else if (year % 4 == 0) {
        flag = true;
    }
    return flag;
}

int main(void)
{ 
    while (true) {
        int x, y;
        bool exist = false;
        scanf("%d%d", &x, &y);
        if (x == 0 && y == 0) {
            break;
        }
        for (int i = x;i <= y; ++i) {
            bool flag = judge(i);
	    if (flag == true) {
                printf("%d\n", i);
                exist = true;
                } 
            }
            if (exist == 0) {
            printf("NA\n");
            }
        printf("\n");
    }   
    return 0;        
}

C++: #include <functional>
#include <algorithm>
#include <iostream>
#include <numeric>
#include <iomanip>
#include <utility>
#include <cstdlib>
#include <sstream>
#include <bitset>
#include <vector>
#include <cstdio>
#include <ctime>
#include <queue>
#include <deque>
#include <cmath>
#include <stack>
#include <list>
#include <map>
#include <set>

using namespace std;

typedef vector<int> vi;
typedef pair<int,int> pii;
typedef long long ll;

#define dump(x)  cerr << #x << " = " << (x) << endl
#define rep(i,n) for(int i=0;i<(n);i++)
#define all(a)  (a).begin(),(a).end()
#define pb push_back

bool isLeep(int n){
    if((n%4==0 && n%100!=0) || n%400==0){
        return true;
    }
    else return false;
}


int main() {
    int a,b;
    while(cin>>a>>b){
        if(a==0 && b==0)break;
        
        int c=0;
        for(int i=a;i<=b;i++){
            if(isLeep(i)){
                c++;
                cout<<i<<endl;
            }
        }
        if(c==0)cout<<"NA"<<endl;
        cout<<endl;
    }
    
    return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <complex>
#include <cmath>
#include <limits>
#include <ctime>
using namespace std;
 
#define rep(i,a,n) for(int i=a; i<n; i++)
#define repr(i,a,n) for(int i=a; i>=n; i--)
#define pb(a) push_back(a)
#define fr first
#define sc second
#define INF 999999999
 
#define X real()
#define Y imag()
#define EPS (1e-10)
#define EQ(a,b) (abs((a) - (b)) < EPS)
#define EQV(a,b) ( EQ((a).X, (b).X) && EQ((a).Y, (b).Y) )
#define LE(n, m) ((n) < (m) + EPS)
#define GE(n, m) ((n) + EPS > (m))
 
typedef vector<int> VI;
typedef vector<VI> MAT;
typedef pair<int, int> pii;
typedef long long int ll;
 
typedef complex<double> P;
typedef pair<P, P> L;
typedef pair<P, double> C;
 
int dy[]={0, 0, 1, -1};
int dx[]={1, -1, 0, 0};
int const MOD = 1000000007;
 
namespace std {
    bool operator<(const P a, const P b) {
        return a.X != b.X ? a.X < b.X : a.Y < b.Y;
    }
}
 
int main() {
    int a,b;
    while(cin >> a >> b) {
        if(a == 0 && b == 0) break;
        vector<int> ans;
        rep(i,a,b+1) {
            if(i % 400 == 0) ans.pb(i);
            else if(i % 100 != 0 && i % 4 == 0) ans.pb(i);
        }
        if(ans.empty()) cout << "NA" << endl;
        else {
            rep(i,0,ans.size()) cout << ans[i] << endl;
        }
        cout << endl;
    }
    return 0;
}

C++: #include <cstdio>
#include <vector>
#include <algorithm>
#include <cstring>
#include <string>
#include <cctype>
#include <sstream>
#include <cmath>
#include <climits>
#include <set>
#include <iostream>
#include <map>
#include <functional>
#include <cstdlib>
#include <numeric>
#include <queue>
#include <complex>
#include <sstream>
#include <stack>

using namespace std;

#define reep(i,f,n) for(int i=f; i<int(n); ++i)
#define rep(i,n) reep(i,0,n)

typedef vector<int> vi;
typedef pair<int, int> pii;
typedef complex<double> Point;

int main()
{
	int a, b;
	for(int i=0; scanf("%d%d", &a, &b), a&b; ++i){
		bool output = false;
		if(i)
			puts("");

		reep(j, a, b+1){
			if(j%4==0 && (j%100!=0 || j%400==0)){
				printf("%d\n", j);
				output = true;
			}
		}

		if(!output)
			puts("NA");
	}

	return 0;
}

C++: #include <iostream>
using namespace std;

int main()
{
	int a, b, cou;
	while (cin >> a >> b, a + b){
		cou = 0;
		for (int i = a; i <= b; i++){
			if (i % 400 == 0){
			 cout << i << endl;
			 cou++;
			}
			else if (i % 4 == 0 && i % 100){
			 cout << i << endl;
			 cou++;
			}
		}
		if (cou == 0) cout << "NA" << endl;
	}
	return (0);
}