from collections import deque, defaultdict, Counter
from bisect import bisect_left, bisect_right
from itertools import permutations, combinations, groupby
from functools import cache
from heapq import heappop, heappush
import math, sys
input = lambda: sys.stdin.readline().rstrip("\r\n")
def printl(li, sep=" "): print(sep.join(map(str, li)))
_int = lambda x: int(x)-1
MOD = 998244353 #10**9+7
INF = 1<<60
Yes, No = "Yes", "No"

# https://github.com/tatyam-prime/SortedSet/blob/main/SortedMultiset.py
import math
from bisect import bisect_left, bisect_right
from typing import Generic, Iterable, Iterator, TypeVar
Type = TypeVar('Type')

class SortedMultiset(Generic[Type]):
    BUCKET_RATIO = 16
    SPLIT_RATIO = 24
    
    def __init__(self, a: Iterable[Type] = []) -> None:
        # Make a new SortedMultiset from iterable. / O(N) if sorted / O(N log N)
        a = list(a)
        n = self.size = len(a)
        if any(a[i] > a[i + 1] for i in range(n - 1)):
            a.sort()
        num_bucket = int(math.ceil(math.sqrt(n / self.BUCKET_RATIO)))
        self.a = [a[n * i // num_bucket : n * (i + 1) // num_bucket] for i in range(num_bucket)]

    def __iter__(self) -> Iterator[Type]:
        for i in self.a:
            for j in i: yield j

    def __reversed__(self) -> Iterator[Type]:
        for i in reversed(self.a):
            for j in reversed(i): yield j
    
    def __eq__(self, other) -> bool:
        return list(self) == list(other)
    
    def __len__(self) -> int:
        return self.size
    
    def __repr__(self) -> str:
        return 'SortedMultiset' + str(self.a)
    
    def __str__(self) -> str:
        s = str(list(self))
        return '{' + s[1 : len(s) - 1] + '}'

    def _position(self, x: Type) -> tuple[list[Type], int, int]:
        # return the bucket, index of the bucket and position in which x should be. self must not be empty.
        for i, a in enumerate(self.a):
            if x <= a[-1]: break
        return (a, i, bisect_left(a, x))

    def __contains__(self, x: Type) -> bool:
        if self.size == 0: return False
        a, _, i = self._position(x)
        return i != len(a) and a[i] == x

    def count(self, x: Type) -> int:
        # Count the number of x.
        return self.index_right(x) - self.index(x)

    def add(self, x: Type) -> None:
        # Add an element. / O(√N)
        if self.size == 0:
            self.a = [[x]]
            self.size = 1
            return
        a, b, i = self._position(x)
        a.insert(i, x)
        self.size += 1
        if len(a) > len(self.a) * self.SPLIT_RATIO:
            mid = len(a) >> 1
            self.a[b:b+1] = [a[:mid], a[mid:]]
    
    def _pop(self, a: list[Type], b: int, i: int) -> Type:
        ans = a.pop(i)
        self.size -= 1
        if not a: del self.a[b]
        return ans

    def discard(self, x: Type) -> bool:
        # Remove an element and return True if removed. / O(√N)
        if self.size == 0: return False
        a, b, i = self._position(x)
        if i == len(a) or a[i] != x: return False
        self._pop(a, b, i)
        return True

    def lt(self, x: Type) -> Type | None:
        # Find the largest element < x, or None if it doesn't exist.
        for a in reversed(self.a):
            if a[0] < x:
                return a[bisect_left(a, x) - 1]

    def le(self, x: Type) -> Type | None:
        # Find the largest element <= x, or None if it doesn't exist.
        for a in reversed(self.a):
            if a[0] <= x:
                return a[bisect_right(a, x) - 1]

    def gt(self, x: Type) -> Type | None:
        # Find the smallest element > x, or None if it doesn't exist.
        for a in self.a:
            if a[-1] > x:
                return a[bisect_right(a, x)]

    def ge(self, x: Type) -> Type | None:
        # Find the smallest element >= x, or None if it doesn't exist.
        for a in self.a:
            if a[-1] >= x:
                return a[bisect_left(a, x)]
    
    def __getitem__(self, i: int) -> Type:
        # Return the i-th element.
        if i < 0:
            for a in reversed(self.a):
                i += len(a)
                if i >= 0: return a[i]
        else:
            for a in self.a:
                if i < len(a): return a[i]
                i -= len(a)
        raise IndexError
    
    def pop(self, i: int = -1) -> Type:
        # Pop and return the i-th element.
        if i < 0:
            for b, a in enumerate(reversed(self.a)):
                i += len(a)
                if i >= 0: return self._pop(a, ~b, i)
        else:
            for b, a in enumerate(self.a):
                if i < len(a): return self._pop(a, b, i)
                i -= len(a)
        raise IndexError

    def index(self, x: Type) -> int:
        # Count the number of elements < x.
        ans = 0
        for a in self.a:
            if a[-1] >= x:
                return ans + bisect_left(a, x)
            ans += len(a)
        return ans

    def index_right(self, x: Type) -> int:
        # Count the number of elements <= x.
        ans = 0
        for a in self.a:
            if a[-1] > x:
                return ans + bisect_right(a, x)
            ans += len(a)
        return ans

import array
def Mo(N: int, Q: int, _A: list[int], qs: list[tuple[int, int, int, int, str]]):
    B = int(N/(Q**0.5 * 0.8)) + 1
    A = array.array('I', _A)
    qs.sort(key=lambda x: (x[0] // B, x[1] if (x[0] // B) % 2 == 0 else -x[1]))

    # 状態管理変数
    ans = [0] * Q
    cnt = array.array('I', [0] * (max(A) + 1))
    cur_res = 0
    cur_l, cur_r = 0, 0

    S = SortedMultiset()
    T = SortedMultiset()

    def insert(x):
        left = S.le(x)
        right = S.gt(x)
        S.add(x)
        if not left and not right: return
        if left and right:
            T.discard(right-left)
        if left:
            T.add(x-left)
        if right:
            T.add(right-x)
    
    def discard(x):
        S.discard(x)
        left = S.le(x)
        right = S.gt(x)
        if not left and not right: return
        if left and right:
            T.add(right-left)
        if left:
            T.discard(x-left)
        if right:
            T.discard(right-x)
    
    def answer(x, c):
        if c == "L":
            res = T.le(x)
        else:
            res = T.ge(x)
        if res == None: res = -1
        return res

    # クエリ処理 (インライン展開版)
    # 関数 add/delete を作らず、直接 while の中にロジックを書く
    for l, r, idx, x, c in qs:
        # [l, r) -> [l-1, r)
        while cur_l > l:
            cur_l -= 1
            val = A[cur_l]
            insert(val)
        # [l, r) -> [l, r+1)
        while cur_r < r:
            val = A[cur_r]
            insert(val)
            cur_r += 1
        # [l, r) -> [l+1, r)
        while cur_l < l:
            val = A[cur_l]
            discard(val)            
            cur_l += 1
        # [l, r) -> [l, r-1)
        while cur_r > r:
            cur_r -= 1
            val = A[cur_r]
            discard(val)
        ans[idx] = answer(x, c)
    return ans
def ctypes(li, types):
    assert len(li) == len(types)
    return [t(a) for a, t in zip(li, types)]
def tinput(*types):
    li = input().split()
    return ctypes(li, types)

N, Q = map(int, input().split())
A = list(map(int, input().split()))
qs = []
for i in range(Q):
    l, r, x, c = tinput(_int, _int, int, str)
    qs.append((l, r+1, i, x, c))

ans = Mo(N, Q, A, qs)
printl(ans, "\n")