#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 2e5 + 100;
struct node {
    int l, r;
    int mx;
} tree[4 * N];
int gra[N];

void pushup(int u) {
    tree[u].mx = max(tree[u << 1].mx, tree[u << 1 | 1].mx);
}

void build(int u, int l, int r) {
    tree[u].l = l;
    tree[u].r = r;
    if (l == r) {
        tree[u].mx = gra[l];
        return;
    }
    int mid = (l + r) >> 1;
    build(u << 1, l, mid);
    build(u << 1 | 1, mid + 1, r);
    pushup(u);
}

void modify(int u, int a, int w) {
    if (tree[u].l == a && tree[u].r == a) {
        tree[u].mx = w;
        return;
    }
    int mid = (tree[u].l + tree[u].r) >> 1;
    if (a <= mid) modify(u << 1, a, w);
    else modify(u << 1 | 1, a, w);
    pushup(u);
}

int query(int u, int a, int b) {
    if (tree[u].l >= a && tree[u].r <= b) return tree[u].mx;

    int ans = INT_MIN; // 初始值改为最小值
    int mid = (tree[u].l + tree[u].r) >> 1;
    if (mid >= a) ans = max(ans, query(u << 1, a, b));
    if (mid < b) ans = max(ans, query(u << 1 | 1, a, b));
    return ans;
}

int main() {
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; i++) cin >> gra[i];
    build(1, 1, n);
    
    while (m--) {
        char in;
        cin >> in;
        if (in == 'Q') {
            int a, b;
            cin >> a >> b;
            cout << query(1, a, b) << "\n";
        } else {
            int a, b;
            cin >> a >> b;
            if(gra[a]<b)
            modify(1, a, b); // 更新线段树
        }
    }
    return 0;
}