// geminiによりPythonからC++に翻訳

#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>

using namespace std;

// 階層型ビットセットの最大範囲 (2^24 = 16,777,216)
const int MAX_VAL = 1 << 24;
const int D_SIZE = 20000005;

struct HierarchicalBitset {
    vector<uint64_t> layers[4];

    HierarchicalBitset() {
        layers[0].resize(1);
        layers[1].resize(64);
        layers[2].resize(4096);
        layers[3].resize(262144);
    }

    void add(int a) {
        for (int i = 3; i >= 0; --i) {
            int a0 = a & 63;
            a >>= 6;
            layers[i][a] |= (1ULL << a0);
        }
    }

    void dec(int a) {
        for (int i = 3; i >= 0; --i) {
            int a0 = a & 63;
            a >>= 6;
            layers[i][a] ^= (1ULL << a0);
            if (layers[i][a]) break; // 上位層がまだ0でなければ停止
        }
    }

    // Predecessor: a以下の最大値 (Pythonのbslに相当)
    int bsl(int a) {
        if (a < 0) return -1;
        // aを含まない「未満」を探す場合は a -= 1 するが、元のコードは a+1 してから探索
        // ここでは inclusive (a以下) として実装
        for (int i = 3; i >= 0; --i) {
            uint64_t mask = (1ULL << (a & 63)) | ((1ULL << (a & 63)) - 1);
            uint64_t x = layers[i][a >> 6] & mask;
            if (x) {
                int rep = ((a >> 6) << 6) | (63 - __builtin_clzll(x));
                for (int j = i + 1; j < 4; ++j) {
                    rep = (rep << 6) | (63 - __builtin_clzll(layers[j][rep]));
                }
                return rep;
            }
            a = (a >> 6) - 1;
            if (a < 0) break;
        }
        return -1;
    }

    // Successor: a以上の最小値 (Pythonのbsrに相当)
    int bsr(int a) {
        if (a >= MAX_VAL) return -1;
        for (int i = 3; i >= 0; --i) {
            uint64_t mask = ~((1ULL << (a & 63)) - 1);
            uint64_t x = layers[i][a >> 6] & mask;
            if (x) {
                int rep = ((a >> 6) << 6) | __builtin_ctzll(x);
                for (int j = i + 1; j < 4; ++j) {
                    rep = (rep << 6) | __builtin_ctzll(layers[j][rep]);
                }
                return rep;
            }
            a = (a >> 6) + 1;
            if (a >= (1 << (6 * i))) break;
        }
        return -1;
    }
};

int D[D_SIZE];
int cnt0 = 0;
HierarchicalBitset X, Y;

void f0(int a) {
    D[a]++;
    if (D[a] > 1) {
        cnt0++;
        return;
    }
    int al = X.bsl(a - 1);
    int ar = X.bsr(a + 1);
    X.add(a);

    if (al != -1 && ar != -1) {
        int diff = ar - al;
        if (--D[10000000 + diff] == 0) Y.dec(diff);
    }
    if (al != -1) {
        int diff = a - al;
        if (++D[10000000 + diff] == 1) Y.add(diff);
    }
    if (ar != -1) {
        int diff = ar - a;
        if (++D[10000000 + diff] == 1) Y.add(diff);
    }
}

void f1(int a) {
    D[a]--;
    if (D[a] > 0) {
        cnt0--;
        return;
    }
    X.dec(a);
    int al = X.bsl(a - 1);
    int ar = X.bsr(a + 1);

    if (al != -1 && ar != -1) {
        int diff = ar - al;
        if (++D[10000000 + diff] == 1) Y.add(diff);
    }
    if (al != -1) {
        int diff = a - al;
        if (--D[10000000 + diff] == 0) Y.dec(diff);
    }
    if (ar != -1) {
        int diff = ar - a;
        if (--D[10000000 + diff] == 0) Y.dec(diff);
    }
}

struct Query {
    int t, l, r, x, id;
};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, q;
    cin >> n >> q;
    vector<int> A(n);
    for (int i = 0; i < n; ++i) cin >> A[i];

    int block_size = max(1, (int)(n / sqrt(q + 1)));
    vector<Query> queries(q);
    for (int i = 0; i < q; ++i) {
        string c;
        cin >> queries[i].l >> queries[i].r >> queries[i].x >> c;
        queries[i].l--;
        queries[i].t = (c == "L" ? 0 : 1);
        queries[i].id = i;
    }

    sort(queries.begin(), queries.end(), [&](const Query& a, const Query& b) {
        int ablock = a.l / block_size;
        int bblock = b.l / block_size;
        if (ablock != bblock) return ablock < bblock;
        return (ablock % 2 == 0) ? (a.r < b.r) : (a.r > b.r);
    });

    vector<int> ans(q);
    int nl = 0, nr = 0;
    for (auto& qry : queries) {
        while (qry.l < nl) f0(A[--nl]);
        while (nr < qry.r) f0(A[nr++]);
        while (nl < qry.l) f1(A[nl++]);
        while (qry.r < nr) f1(A[--nr]);

        int res;
        if (qry.t == 0) {
            res = Y.bsl(qry.x);
            if (cnt0 > 0) res = max(res, 0);
        } else {
            res = Y.bsr(qry.x);
        }
        ans[qry.id] = res;
    }

    for (int x : ans) cout << x << "\n";

    return 0;
}