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 

n,m=list(map(int,stdin.readline().split()))
a=list(map(int,stdin.readline().split()))

pre=[]
t,index=a[0],0
for i in range(n) :
    index=index if a[i]==t else i
    t=a[i]
    pre.append(index)

prt=[]
for i in range(m) :
    l,r,x=list(map(int,stdin.readline().split()))
    L=pre[r-1]
    if a[r-1]==x :
        sl=pre[r-1]+1
        if sl<=l :
            prt.append(str(-1))
            continue
        r=sl-1
    prt.append(str(r))

print("\n".join(prt))