D open 51

/*
┓┏┓┏┓┃
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┓┏┓┏┓┃＼○／
┛┗┛┗┛┃ / /
┓┏┓┏┓┃ノ
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      MIPTCLASSICMIPTCLASSICMIPTCLASSICMIPTCLASSICMIPTCLASSICMIPTCLASSIC
*/

// #define pragma

#ifdef pragma
#pragma GCC optimize("Ofast")
#pragma GCC optimize("no-stack-protector")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("unroll-loops")
#pragma GCC diagnostic ignored "-Wunused-result"
#endif // pragma

#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define ll long long
#define all(x) begin(x), end(x)
#define pb push_back
#define x first
#define y second
#define int long long
#define zero(two) memset(two, 0, sizeof(two))

using namespace std;
using namespace __gnu_pbds;


typedef vector<int> vi;
typedef vector<bool> vb;
typedef pair<int, int> pii;
typedef long double ld;
typedef vector<vi> matrix;
template<typename T>
using kawaii_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

const ld PI = atan2(0, -1);

void seriy() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cout << fixed << setprecision(10);
    #if 1
        freopen("input", "r", stdin);
        freopen("output", "w", stdout);
    #endif
}

struct rrq {
    int t, l, r, id;
};

struct crq {
    int t, pos, val;
};

const int INF = 1e9 + 7;
const int MAXN = 1e6 + 100;

int k, kt;
vi addpos;
matrix add;
vi a, ccc(MAXN);
int curpos = 0;
vector<crq> crqs;
int curl = 1, curr = 0, curt = 0;

bool cmp(rrq a, rrq b) {
    if(a.t / kt != b.t / kt) {
        return a.t < b.t;
    }
    else if(a.l / k != b.l / k) {
        return a.l < b.l;
    }
    return a.r < b.r;
}

void addLeft(int pos) {
    pos = a[pos];
    ccc[pos]++;
    // if(pos == curpos) {
    //     while(ccc[curpos]) {
    //         curpos++;
    //     }
    // }
}

void addRight(int pos) {
    addLeft(pos);
}

void delLeft(int pos) {
    pos = a[pos];
    ccc[pos]--;
    // if(ccc[pos] == 0 && pos < curpos) {
    //     curpos = pos;
    // }
}

void delRight(int pos) {
    delLeft(pos);
}

void addT(int num) {
    int pos = crqs[num].pos;
    int val = crqs[num].val;
    int pv = a[pos];
    addpos[pos]++;
    a[pos] = val;
    if(pos >= curl && pos <= curr) {
        addLeft(pos);
    }
    a[pos] = pv;
    if(pos >= curl && pos <= curr) {
        delLeft(pos);
    }
    a[pos] = val;
}

void delT(int num) {
    int pos = crqs[num].pos;
    int pv = a[pos];
    addpos[pos]--;
    a[pos] = add[pos][addpos[pos]];
    if(pos >= curl && pos <= curr) {
        addLeft(pos);
    }
    a[pos] = pv;
    if(pos >= curl && pos <= curr) {
        delLeft(pos);
    }
    a[pos] = add[pos][addpos[pos]];
}

int answer() {
    for(int i = 0; ; i++) {
        if(!ccc[i]) {
            return i;
        }
    }
}

signed main() {
    seriy();
    int n, q;
    cin >> n >> q;
    a.resize(n);
    add.resize(n);
    addpos.resize(n, 0);
    for(int i = 0; i < n; i++) {
        cin >> a[i];
        add[i].pb(a[i]);
    }
    vi l(q), r(q);
    int tt = 0;
    vector<rrq> rqs;
    for(int i = 0; i < q; i++) {
        char rq;
        cin >> rq;
        cin >> l[i] >> r[i];
        l[i]--;
        if(rq == '!') {
            crqs.pb({tt + 1, l[i], r[i]});
            add[l[i]].pb(r[i]);
//            cerr << l[i] << " " << r[i] << '\n';
            tt++;
        }
        else {
            r[i]--;
            rqs.pb({tt, l[i], r[i], i});
        }
    }
    int num = 0;
    k = pow(n, 2. / 3.);
    kt = pow(tt, 2. / 3.) + 1;
    sort(all(rqs), cmp);
    vi ans(q, -1);
    for(int i = 0; i < rqs.size(); i++) {


        while(curl > rqs[i].l) {
            curl--;
            addLeft(curl);
        }
        while(curr < rqs[i].r) {
            curr++;
            addRight(curr);
        }
        while(curl < rqs[i].l) {
            delLeft(curl);
            curl++;
        }
        while(curr > rqs[i].r) {
            delRight(curr);
            curr--;
        }
        while(curt < rqs[i].t) {
            addT(curt);
            curt++;
        }
        while(curt > rqs[i].t) {
            curt--;
            delT(curt);
        }
//        for(auto j : a) {
//            cerr << j << " ";
//        }
//        cerr << '\n';
//        cerr << rqs[i].t << " " << rqs[i].l << " " << rqs[i].r << " " << answer() << '\n';
        ans[rqs[i].id] = answer();
    }
    for(auto i : ans) {
        if(i != -1) cout << i << '\n';
    }
    return 0;
}