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/*
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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 l, r, id, tp;
};

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

int k;
vi a, ccc(MAXN);
int curpos = 0;

bool cmp(rrq a, rrq b) {
    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);
}

int answer() {
    return curpos;
}

signed main() {
    seriy();
    int n, q;
    cin >> n >> q;
    a.resize(n);
    int mxx = 0;
    for(int i = 0; i < n; i++) {
        cin >> a[i];
        mxx = max(mxx, a[i]);
    }
    vector<char> rq(q);
    vi l(q), r(q);
    bool wasAssign = 0;
    vector<rrq> rqs(q);
    for(int i = 0; i < q; i++) {
        cin >> rq[i];
        cin >> l[i] >> r[i];
        if(rq[i] == '!') {
            mxx = max(mxx, r[i]);
            wasAssign = 1;
        }
        else {
            l[i]--, r[i]--;
        }
        rqs[i] = {l[i], r[i], i, tp};
        // cerr << mxx << " " << (rq[i] == '!' && r[i] > 10) << " " << r[i] << '\n';
    }
    int num = 0;
    if(!wasAssign) {
        k = sqrt(n);
        sort(all(rqs), cmp);
        vi ans(q);
        int curl = 1, curr = 0;
        for(int i = 0; i < q; 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--;
            }
            ans[rqs[i].id] = answer();
        }
        for(auto i : ans) {
            cout << i << '\n';
        }
    }
    else if(mxx > 10) {
        while(q--) {
            if(rq[num] == '?') {
                int mn = INF, mx = 0;
                vi cnt(MAXN + 1);
                for(int i = l[num]; i <= r[num]; i++) {
                    mn = min(mn, a[i]);
                    mx = max(mx, a[i]);
                    cnt[a[i]]++;
                }
                int ans = MAXN;
                for(int i = mn; i < MAXN; i++) {
                    if(!cnt[i]) {
                        ans = i;
                        break;
                    }
                }
                if(mn == 0) {
                    cout << ans << '\n';
                }
                else {
                    cout << "0\n";
                }
            }
            else {
                l[num]--;
                a[l[num]] = r[num];
            }
            num++;
        }
    }
    else {
        vector<set<int>> vs(11);
        for(int i = 0; i < n; i++) {
            vs[a[i]].insert(i);
        }
        while(q--) {
            if(rq[num] == '?') {
                int ans = 11;
                for(int i = 0; i < 11; i++) {
                    // cerr << (vs[i].lower_bound(l[num]) == vs[i].end()) << '\n';
                    if(vs[i].lower_bound(l[num]) == vs[i].end() || (*vs[i].lower_bound(l[num])) > r[num]) {
                        ans = i;
                        break;
                    }
                }
                // cerr << '\n';
                cout << ans << '\n';
            }
            else {
                l[num]--;
                int ans = 0;
                for(int i = 0; i < 11; i++) {
                    if(vs[i].lower_bound(l[num]) != vs[i].end() && (*vs[i].lower_bound(l[num])) == l[num]) {
                        ans = i;
                        break;
                    }
                }
                vs[ans].erase(l[num]);
                vs[r[num]].insert(l[num]);
            }
            num++;
        }
    }
    return 0;
}