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


def main():
    n, m = map(int, stdin.readline().split())
    ar = list(map(int, stdin.readline().split()))
    left = [0] * n
    left[0] = -1
    cl = -1
    for i in range(1, n):
        if ar[i] != ar[i - 1]:
            cl = i
        left[i] = cl
    for _ in range(m):
        l, r, val = map(int, stdin.readline().split())
        if ar[r - 1] != val:
            stdout.write(str(r))
        elif left[r - 1] >= l:
            stdout.write(str(left[r - 1]))
        else:
            stdout.write('-1')
        stdout.write('\n')


if __name__ == '__main__':
    main()