import java.util.*;
 
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String line = scanner.nextLine();
        int target = scanner.nextInt();
 
        // 用 \\s+ 兼容多个空格；其余保持不变
        String[] parts = line.trim().split("\\s+");
        int n = parts.length;
        int[] A = new int[n];
        for (int i = 0; i < n; i++) {
            A[i] = Integer.parseInt(parts[i]);
        }
 
        Map<Integer, List<Integer>> map = new HashMap<>();
        List<int[]> pairs = new ArrayList<>();
 
        for (int j = 0; j < n; j++) {
            int need = A[j] - target;
            if (map.containsKey(need)) {
                List<Integer> indices = map.get(need);
                for (int i : indices) {
                    pairs.add(new int[]{i, j});
                }
            }
 
            // 只新增这段：同时处理 A[i] - A[j] == target 的情况
            int need2 = A[j] + target;
            if (map.containsKey(need2)) {
                List<Integer> indices = map.get(need2);
                for (int i : indices) {
                    pairs.add(new int[]{i, j});
                }
            }
 
            if (!map.containsKey(A[j])) {
                map.put(A[j], new ArrayList<>());
            }
            map.get(A[j]).add(j);
        }
 
        System.out.print("[");
        StringJoiner sj = new StringJoiner(", ");
        for (int[] pair : pairs) {
            sj.add("(" + pair[0] + ", " + pair[1] + ")");
        }
        System.out.print(sj.toString());
        System.out.println("]");
    }
}
 

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