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 main() {
  int n, m, l, r, x;
  scanf("%d%d", &n, &m);
  vector<int> a(n + 1, 0);
  vector<int> prevDiff(n + 1, 0);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
    if (a[i] != a[i - 1]) {
      prevDiff[i] = i - 1;
    } else {
      prevDiff[i] = prevDiff[i - 1];
    }
  }
  for (int i = 1; i <= m; i++) {
    scanf("%d%d%d", &l, &r, &x);
    if (x != a[r]) {
      printf("%d\n", r);
    } else {
      if (prevDiff[r] >= l) {
        printf("%d\n", prevDiff[r]);
      } else {
        printf("-1\n");
      }
    }
  }
}