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:
import sys
input = sys.stdin.readline

n, m = map(int, input().split())
a = list(map(int, input().split()))
b, c = [0], []
now = 0
for j in range(n - 1):
    if a[j] ^ a[j + 1]:
        now += 1
        c.append(j)
    b.append(now)
c.append(n)
for _ in range(m):
    l, r, p = map(int, input().split())
    x = c[b[l - 1]]
    y = x + 1
    if a[l - 1] ^p:
        ans = l
    elif y >= r:
        ans = -1
    else:
        ans = x + 1 if a[x] ^ p else y + 1
    print(ans)