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


def preprocess(arr):
    left_i = -1
    prev = arr[0]
    preprocessed = []
    for i, k in enumerate(arr):
        if prev != k:
            prev = k
            left_i = i
        preprocessed.append(left_i)
    return preprocessed


def query(arr, pre, l, r, x):
    if arr[r-1] != x:
        return r
    if pre[r-1] >= l:
        return pre[r-1]
    return -1


def solve():
    n, m = map(int, sys.stdin.readline().split())
    arr = list(map(int, sys.stdin.readline().split()))
    pre = preprocess(arr)
    for _ in range(m):
        l, r, x = map(int, sys.stdin.readline().split())
        yield str(query(arr, pre, l, r, x))


def main():
    sys.stdout.write("\n".join(solve()))


main()