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 PYTHON3):

Solution:
from sys import stdin, stdout

n, m = map(int, input().split())

a = [0]

a.extend(list(map(int, stdin.readline().split())))

a[0] = a[1] + 1

p = list(range(n + 1))

i, j = n, n
while i > 0:
	while a[i] == a[j] and j >= 0:
		j -= 1
	for k in range(j + 1, i + 1):
		p[k] = j
	i = j

for _ in range(m):
	l, r, x = map(int, stdin.readline().split())
	if a[r] != x:
		stdout.write(str(r))
	else:
		if p[r] >= l:
			stdout.write(str(p[r]))
		else:
			stdout.write('-1')
	stdout.write('\n')