Problem: You are given array a with n integers and m queries. The i-th query is given with three integers li, ri, xi.

For the i-th query find any position pi (li ≤ pi ≤ ri) so that api ≠ xi.

Input

The first line contains two integers n, m (1 ≤ n, m ≤ 2·105) — the number of elements in a and the number of queries.

The second line contains n integers ai (1 ≤ ai ≤ 106) — the elements of the array a.

Each of the next m lines contains three integers li, ri, xi (1 ≤ li ≤ ri ≤ n, 1 ≤ xi ≤ 106) — the parameters of the i-th query.

Output

Print m lines. On the i-th line print integer pi — the position of any number not equal to xi in segment [li, ri] or the value  - 1 if there is no such number.

Examples

Input

6 4
1 2 1 1 3 5
1 4 1
2 6 2
3 4 1
3 4 2


Output

2
6
-1
4

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
const int NMAX = 200006;
int n, query, poz[NMAX], a[NMAX];
int main() {
  int x, st, dr, val, i;
  scanf("%d%d", &n, &query);
  poz[1] = -1;
  scanf("%d", &a[1]);
  n--;
  i = 1;
  while (n--) {
    ++i;
    scanf("%d", &a[i]);
    x = a[i];
    if (x != a[i - 1])
      poz[i] = i - 1;
    else
      poz[i] = poz[i - 1];
  }
  while (query--) {
    scanf("%d%d%d", &st, &dr, &val);
    if (a[dr] != val)
      printf("%d\n", dr);
    else if (poz[dr] >= st)
      printf("%d\n", poz[dr]);
    else
      printf("-1\n");
  }
  return 0;
}