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;
int n, m, a[200010], p[200010];
void Init() {
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; ++i) scanf("%d", a + i);
  p[n] = n;
  for (int i = n - 1; i; --i) p[i] = a[i] == a[i + 1] ? p[i + 1] : i;
}
void Query() {
  int i, l, r, x;
  for (i = 1; i <= m; ++i) {
    scanf("%d%d%d", &l, &r, &x);
    if (a[l] == x) {
      if (p[l] >= r)
        printf("-1\n");
      else
        printf("%d\n", p[l] + 1);
    } else
      printf("%d\n", l);
  }
}
int main() {
  Init();
  Query();
  return 0;
}