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 = [N + 1 for _ in range(N)]
idx = N + 1

for i in range(N - 1)[::-1]:
    if A[i] != A[i + 1]:
        idx = i + 1
    B[i] = idx

res = []

for _ in range(M):
    l, r, x = map(int, input().split())
    if A[l - 1] != x:
        res.append(l)
    elif B[l - 1] <= r - 1:
        res.append(B[l - 1] + 1)
    else:
        res.append(-1)

print('\n'.join(map(str, res)))