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 maxn = 2e5 + 10;
const int inf = 1e9;
const long long INF = 1E18;
int a[maxn], dp[maxn];
int main() {
  int n, m;
  cin >> n >> m;
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
  dp[n] = n + 1;
  for (int i = n - 1; i >= 1; i--) {
    int x = a[i];
    if (x == a[i + 1])
      dp[i] = dp[i + 1];
    else
      dp[i] = i + 1;
  }
  for (int i = 0; i < m; i++) {
    int l, r, x;
    scanf("%d%d%d", &l, &r, &x);
    if (a[l] != x) {
      printf("%d\n", l);
    } else {
      if (dp[l] > r)
        puts("-1");
      else {
        printf("%d\n", dp[l]);
      }
    }
  }
  return 0;
}