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:
from sys import *
n,m=map(int,raw_input().split())
lst=[int(y) for y in stdin.readline().split()]
arr=[0]*(n+2)

for i in range(1,n):
  if lst[i]==lst[i-1]:
    arr[i]=arr[i-1]
  else:
    arr[i]=i-1 
#print arr[11]
ans=[]

for i in range(0,m):
  l,r,x=[int(y) for y in stdin.readline().split()]
  if lst[r-1]!=x:

    ans.append((str(r)))
  #  stdout.write("\n") 
  else:

    if arr[r-1]>=l-1 and lst[arr[r-1]]!=x:
      ans.append(str(arr[r-1]+1))
     # stdout.write("\n") 
    else:
      ans.append(str(-1))
      #stdout.write("\n") 
print "\n".join(ans)