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

arr = map(int, raw_input().split())

queries = []
for i in range(m):
    queries.append(tuple(map(int, raw_input().split())))

dp = [-1]
for i, a in enumerate(arr[1:]):
    if arr[i] != a:
        dp.append(i)
    else:
        dp.append(dp[-1])

for l, r, x in queries:
    l -= 1
    r -= 1
    if arr[r] != x:
        print r + 1
    else:
        if dp[r] >= l:
            print dp[r] + 1
        else:
            print -1