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 PYTHON):

Solution:
__author__ = 'aste'


def main():
    n, m = map(int, raw_input().split())
    a = map(int, raw_input().split())

    p = [-1]*n
    for i in range(1, n):
        if a[i - 1] == a[i]:
            p[i] = p[i - 1]
        else:
            p[i] = i - 1

    for i in range(0, m):
        l, r, x = map(int, raw_input().split())
        if a[r - 1] != x:
            print r
        elif p[r - 1] < l - 1:
            print -1
        else:
            print p[r - 1] + 1

main()