#include <fstream>

#include <algorithm>
#include <set>
#include <vector>
#include <queue>

using namespace std;

const int nmax = int(3e5);
struct node {
    multiset<int> s;
    vector<int> upin, upout;
};

vector<node> a;


void updatein(int node,int l,int r,int x,int y, int z) {
    if (r < x || l > y) return;
    if (x <= l && r <= y) {
        a[node].s.insert(z);
        a[node].upin.push_back(z);
        return;
    }

    int ls = node << 1;
    int rs = ls + 1;
    int mid = (l + r) >> 1;
    updatein( ls, l, mid, x, y, z);
    updatein( rs, mid + 1, r, x, y, z);
}

void updateout(int node,int l,int r,int x,int y, int z) {
    if (r < x || l > y) return;
    if (x <= l && r <= y) {
        a[node].s.erase(z);
        a[node].upout.push_back(z);
        return;
    }

    int ls = node << 1;
    int rs = ls + 1;
    int mid = (l + r) >> 1;
    updateout( ls, l, mid, x, y, z);
    updateout( rs, mid + 1, r, x, y, z);
}

int query(int node,int l,int r,int x) {
    if (l == r) {
        return a[node].s.empty() ? 0 : (*a[node].s.begin());
    }


    int ls = node << 1;
    int rs = ls + 1;
    int mid = (l + r) >> 1;
    
    if (!a[node].upin.empty() || !a[node].upout.empty()) {
        for (int& x : a[node].upin) {
            a[ls].upin.push_back(x);
            a[rs].upin.push_back(x);
            a[ls].s.insert(x);
            a[rs].s.insert(x);
        }

        for (int& x : a[node].upout) {
            a[ls].upout.push_back(x);
            a[rs].upout.push_back(x);
            a[ls].s.erase(x);
            a[rs].s.erase(x);
        }

        a[node].upin.clear();
        a[node].upout.clear();

    }
    
    
    if (x <= mid)
        return query(ls, l, mid, x);

    return query(rs, mid + 1, r, x);
}


int main() {
    ifstream cin("invazia.in");
    ofstream cout("invazia.out");
    int N, M;
    cin >> N >> M;
     int p = 1;
    while ( p <= N) {
        p <<= 1;
    }
    p <<= 1;
    a.resize(p);
    char c;
    int x, y, z;  
    vector< tuple<int,int,int> > st;
    while (M--) {
        cin >> c;
        if (c == 'I') {
            cin >> x >> y >> z;
            st.push_back(make_tuple(x, y, z));
            updatein(1, 1, N, x, y, z);
        } else
        if (c == 'E') {
            tie(x, y, z) = st.back();
            st.pop_back();
            updateout(1, 1, N, x, y, z); 
        
        } else
        if (c == 'R') {
            cin >> x;
            cout << query(1, 1, N, x) << "\n";
        }
    }
    return 0;
}