#line 2 "/Users/noya2/Desktop/Noya2_library/template/template.hpp"
using namespace std;

#include<bits/stdc++.h>
#line 1 "/Users/noya2/Desktop/Noya2_library/template/inout_old.hpp"
namespace noya2 {

template <typename T, typename U>
ostream &operator<<(ostream &os, const pair<T, U> &p){
    os << p.first << " " << p.second;
    return os;
}
template <typename T, typename U>
istream &operator>>(istream &is, pair<T, U> &p){
    is >> p.first >> p.second;
    return is;
}

template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v){
    int s = (int)v.size();
    for (int i = 0; i < s; i++) os << (i ? " " : "") << v[i];
    return os;
}
template <typename T>
istream &operator>>(istream &is, vector<T> &v){
    for (auto &x : v) is >> x;
    return is;
}

void in() {}
template <typename T, class... U>
void in(T &t, U &...u){
    cin >> t;
    in(u...);
}

void out() { cout << "\n"; }
template <typename T, class... U, char sep = ' '>
void out(const T &t, const U &...u){
    cout << t;
    if (sizeof...(u)) cout << sep;
    out(u...);
}

template<typename T>
void out(const vector<vector<T>> &vv){
    int s = (int)vv.size();
    for (int i = 0; i < s; i++) out(vv[i]);
}

struct IoSetup {
    IoSetup(){
        cin.tie(nullptr);
        ios::sync_with_stdio(false);
        cout << fixed << setprecision(15);
        cerr << fixed << setprecision(7);
    }
} iosetup_noya2;

} // namespace noya2
#line 1 "/Users/noya2/Desktop/Noya2_library/template/const.hpp"
namespace noya2{

const int iinf = 1'000'000'007;
const long long linf = 2'000'000'000'000'000'000LL;
const long long mod998 =  998244353;
const long long mod107 = 1000000007;
const long double pi = 3.14159265358979323;
const vector<int> dx = {0,1,0,-1,1,1,-1,-1};
const vector<int> dy = {1,0,-1,0,1,-1,-1,1};
const string ALP = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const string alp = "abcdefghijklmnopqrstuvwxyz";
const string NUM = "0123456789";

void yes(){ cout << "Yes\n"; }
void no(){ cout << "No\n"; }
void YES(){ cout << "YES\n"; }
void NO(){ cout << "NO\n"; }
void yn(bool t){ t ? yes() : no(); }
void YN(bool t){ t ? YES() : NO(); }

} // namespace noya2
#line 2 "/Users/noya2/Desktop/Noya2_library/template/utils.hpp"

#line 6 "/Users/noya2/Desktop/Noya2_library/template/utils.hpp"

namespace noya2{

unsigned long long inner_binary_gcd(unsigned long long a, unsigned long long b){
    if (a == 0 || b == 0) return a + b;
    int n = __builtin_ctzll(a); a >>= n;
    int m = __builtin_ctzll(b); b >>= m;
    while (a != b) {
        int mm = __builtin_ctzll(a - b);
        bool f = a > b;
        unsigned long long c = f ? a : b;
        b = f ? b : a;
        a = (c - b) >> mm;
    }
    return a << std::min(n, m);
}

template<typename T> T gcd_fast(T a, T b){ return static_cast<T>(inner_binary_gcd(std::abs(a),std::abs(b))); }

long long sqrt_fast(long long n) {
    if (n <= 0) return 0;
    long long x = sqrt(n);
    while ((x + 1) * (x + 1) <= n) x++;
    while (x * x > n) x--;
    return x;
}

template<typename T> T floor_div(const T n, const T d) {
    assert(d != 0);
    return n / d - static_cast<T>((n ^ d) < 0 && n % d != 0);
}

template<typename T> T ceil_div(const T n, const T d) {
    assert(d != 0);
    return n / d + static_cast<T>((n ^ d) >= 0 && n % d != 0);
}

template<typename T> void uniq(std::vector<T> &v){
    std::sort(v.begin(),v.end());
    v.erase(unique(v.begin(),v.end()),v.end());
}

template <typename T, typename U> inline bool chmin(T &x, U y) { return (y < x) ? (x = y, true) : false; }

template <typename T, typename U> inline bool chmax(T &x, U y) { return (x < y) ? (x = y, true) : false; }

template<typename T> inline bool range(T l, T x, T r){ return l <= x && x < r; }

} // namespace noya2
#line 8 "/Users/noya2/Desktop/Noya2_library/template/template.hpp"

#define rep(i,n) for (int i = 0; i < (int)(n); i++)
#define repp(i,m,n) for (int i = (m); i < (int)(n); i++)
#define reb(i,n) for (int i = (int)(n-1); i >= 0; i--)
#define all(v) (v).begin(),(v).end()

using ll = long long;
using ld = long double;
using uint = unsigned int;
using ull = unsigned long long;
using pii = pair<int,int>;
using pll = pair<ll,ll>;
using pil = pair<int,ll>;
using pli = pair<ll,int>;

namespace noya2{

/*　~ (. _________ . /)　*/

}

using namespace noya2;


#line 2 "c.cpp"


// 5:28~

#line 2 "/Users/noya2/Desktop/Noya2_library/data_structure/csr.hpp"

#line 4 "/Users/noya2/Desktop/Noya2_library/data_structure/csr.hpp"
#include<ranges>
#line 7 "/Users/noya2/Desktop/Noya2_library/data_structure/csr.hpp"

namespace noya2::internal {

template<class E>
struct csr {
    csr () {}
    csr (int _n) : n(_n) {}
    csr (int _n, int m) : n(_n){
        start.reserve(m);
        elist.reserve(m);
    }
    // ACL style constructor (do not have to call build)
    csr (int _n, const std::vector<std::pair<int,E>> &idx_elem) : n(_n), start(_n + 2), elist(idx_elem.size()) {
        for (auto &[i, e] : idx_elem){
            start[i + 2]++;
        }
        for (int i = 1; i < n; i++){
            start[i + 2] += start[i + 1];
        }
        for (auto &[i, e] : idx_elem){
            elist[start[i + 1]++] = e;
        }
        prepared = true;
    }
    int add(int idx, E elem){
        int eid = start.size();
        start.emplace_back(idx);
        elist.emplace_back(elem);
        return eid;
    }
    void build(){
        if (prepared) return ;
        int m = start.size();
        std::vector<E> nelist(m);
        std::vector<int> nstart(n + 2, 0);
        for (int i = 0; i < m; i++){
            nstart[start[i] + 2]++;
        }
        for (int i = 1; i < n; i++){
            nstart[i + 2] += nstart[i + 1];
        }
        for (int i = 0; i < m; i++){
            nelist[nstart[start[i] + 1]++] = elist[i];
        }
        swap(elist,nelist);
        swap(start,nstart);
        prepared = true;
    }
    const auto operator[](int idx) const {
        return std::ranges::subrange(elist.begin()+start[idx],elist.begin()+start[idx+1]);
    }
    auto operator[](int idx){
        return std::ranges::subrange(elist.begin()+start[idx],elist.begin()+start[idx+1]);
    }
    const auto operator()(int idx, int l, int r) const {
        return std::ranges::subrange(elist.begin()+start[idx]+l,elist.begin()+start[idx]+r);
    }
    auto operator()(int idx, int l, int r){
        return std::ranges::subrange(elist.begin()+start[idx]+l,elist.begin()+start[idx]+r);
    }
    size_t size() const {
        return n;
    }
    int n;
    std::vector<int> start;
    std::vector<E> elist;
    bool prepared = false;
};

} // namespace noya2::internal
#line 7 "c.cpp"

const int nmx = 100'010;
const int bmx = sqrt(nmx);
const int mx = 10'000'010;
// const int mx = 15;
const int lim = sqrt(mx)*4;
int cnt[mx];
// vector<int> cnt(mx);
bool ex[mx];
int id_pcn = 0;
pii pcn[nmx];
int id_big_0 = 0;
int buf_big[2];
int big[2][nmx*4];

void solve(){
    int n, q; in(n,q);
    vector<int> a(n); in(a);
    vector<int> ids(n); iota(all(ids),0);
    ranges::sort(ids, {}, [&](int i){
        return a[i];
    });
    vector<int> pos(n);
    rep(i,n){
        pos[ids[i]] = i;
    }
    vector<int> ls(q), rs(q), xs(q);
    rep(i,q){
        int l, r; in(l,r); l--;
        int x; in(x);
        char c; in(c);
        ls[i] = l, rs[i] = r;
        xs[i] = (c == 'L' ? x : ~x);
    }
    vector<int> qids(q); iota(all(qids),0);
    ranges::sort(qids, {}, [&](int qi){
        return ls[qi];
    });
    internal::csr<int> qs(n/bmx+1);
    for (int qi : qids){
        qs.add(rs[qi]/bmx,qi);
    }
    qs.build();
    vector<int> nxt(n,-1), prv(n,-1);
    auto add = [&](int d){
        cnt[d]++;
        if (d >= lim){
            big[id_big_0][buf_big[id_big_0]++] = d;
        }
    };
    auto del = [&](int d){
        cnt[d]--;
        if (d >= lim){
            big[id_big_0][buf_big[id_big_0]++] = d;
        }
    };
    rep(i,n-1){
        nxt[i] = i+1;
        prv[i+1] = i;
        int d = a[ids[i+1]] - a[ids[i]];
        add(d);
    }
    auto proc = [&](int i){
        int p = pos[i];
        pcn[id_pcn++] = [&] -> pii {
            if (nxt[p] != -1){
                return {p, nxt[p]};
            }
            else if (prv[p] != -1){
                return {p, ~prv[p]};
            }
            else {
                return {-1, p};
            }
        }();
        if (nxt[p] != -1){
            int j = ids[nxt[p]];
            del(a[j] - a[i]);
            prv[nxt[p]] = -1;
        }
        if (prv[p] != -1){
            int j = ids[prv[p]];
            del(a[i] - a[j]);
            nxt[prv[p]] = -1;
        }
        if (nxt[p] != -1 && prv[p] != -1){
            int j = ids[nxt[p]];
            int k = ids[prv[p]];
            add(a[j] - a[k]);
            nxt[prv[p]] = nxt[p];
            prv[nxt[p]] = prv[p];
        }
        nxt[p] = prv[p] = -1;
    };
    auto rollback = [&](){
        auto [prvp, p, nxtp] = [&] -> tuple<int,int,int> {
            auto [pp, np] = pcn[--id_pcn];
            if (pp == -1){
                return {-1, pp, -1};
            }
            else if (np >= 0){
                return {prv[np], pp, np};
            }
            else {
                return {~np, pp, nxt[~np]};
            }
        }();
        prv[p] = prvp;
        nxt[p] = nxtp;
        int i = ids[p];
        if (nxt[p] != -1){
            int j = ids[nxt[p]];
            add(a[j] - a[i]);
            prv[nxt[p]] = p;
        }
        if (prv[p] != -1){
            int j = ids[prv[p]];
            add(a[i] - a[j]);
            nxt[prv[p]] = p;
        }
        if (nxt[p] != -1 && prv[p] != -1){
            int j = ids[nxt[p]];
            int k = ids[prv[p]];
            del(a[j] - a[k]);
        }
    };
    auto query = [&](int x){
        rep(i,buf_big[id_big_0]){
            int d = big[id_big_0][i];
            if (cnt[d] > 0){
                ex[d] = true;
            }
        }
        rep(i,buf_big[id_big_0]){
            int d = big[id_big_0][i];
            if (ex[d]){
                big[id_big_0^1][buf_big[id_big_0^1]++] = d;
                ex[d] = false;
            }
        }
        buf_big[id_big_0] = 0;
        id_big_0 ^= 1;
        if (x >= 0){
            if (x >= lim){
                int ans = -1;
                rep(i,buf_big[id_big_0]){
                    int d = big[id_big_0][i];
                    if (d <= x){
                        chmax(ans,d);
                    }
                }
                if (ans != -1) return ans;
            }
            reb(d,min(lim,x+1)){
                if (cnt[d] > 0){
                    return d;
                }
            }
            return -1;
        }
        else {
            x = ~x;
            if (x < lim){
                repp(d,x,lim){
                    if (cnt[d] > 0){
                        return d;
                    }
                }
            }
            int ans = iinf;
            rep(i,buf_big[id_big_0]){
                int d = big[id_big_0][i];
                if (d >= x){
                    chmin(ans,d);
                }
            }
            if (ans == iinf) return -1;
            return ans;
        }
    };
    int l = 0, r = n;
    vector<int> memo(q);
    reb(bid,n/bmx+1){
        int br = min(n, (bid+1)*bmx);
        while (r > br){
            int i = --r;
            proc(i);
        }
        for (int qi : qs[bid]){
            int il = ls[qi];
            while (l < il){
                int i = l++;
                proc(i);
            }
            int ir = rs[qi];
            while (r > ir){
                int i = --r;
                proc(i);
            }
            memo[qi] = query(xs[qi]);
            while (r < br){
                r++;
                rollback();
            }
        }
        while (l > 0){
            --l;
            rollback();
        }
    }
    rep(i,q){
        out(memo[i]);
    }
}

int main(){
    int t = 1; //in(t);
    while (t--) { solve(); }
}