#pragma comment(linker, "/STACK:1024000000,1024000000")

#include <cstdio>

#include <string>

#include <cstdlib>

#include <cmath>

#include <iostream>

#include <cstring>

#include <set>

#include <queue>

#include <algorithm>

#include <vector>

#include <map>

#include <cctype>

#include <cmath>

#include <stack>

#define lson l,m,rt<<1

#define rson m+1,r,rt<<1|1

#define freopenr freopen("in.txt", "r", stdin)

#define freopenw freopen("out.txt", "w", stdout)

using namespace std;

typedef long long LL;

typedef pair<int, int> P;

const int INF = 0x3f3f3f3f;

const double inf = 0x3f3f3f3f3f3f;

const double PI = acos(-1.0);

const double eps = 1e-8;

const int maxn = 200000 + 5;

const int mod = 1e9 + 7;

const int dr[] = {0, 1, 0, -1, -1, 1, 1, -1};

const int dc[] = {1, 0, -1, 0, 1, 1, -1, -1};

const char *de[] = {"0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"};

int n, m;

const int mon[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

const int monn[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

inline int Min(int a, int b){ return a < b ? a : b; }

inline int Max(int a, int b){ return a > b ? a : b; }

inline LL Min(LL a, LL b){ return a < b ? a : b; }

inline LL Max(LL a, LL b){ return a > b ? a : b; }

inline bool is_in(int r, int c){

    return r >= 0 && r < n && c >= 0 && c < m;

}

int maxv[maxn<<2];

void pushup(int rt){ maxv[rt] = Max(maxv[rt<<1], maxv[rt<<1|1]); }

void build(int l, int r, int rt){

    if(l == r){

        scanf("%d", &maxv[rt]);

        return ;

    }

    int m = (l + r) >> 1;

    build(lson);

    build(rson);

    pushup(rt);

}

void update(int x, int val, int l, int r, int rt){

    if(l == r){

        maxv[rt] = val;

        return ;

    }

    int m = (l + r) >> 1;

    if(x <= m)  update(x, val, lson);

    if(x > m)   update(x, val, rson);

    pushup(rt);

}

int query(int L, int R, int l, int r, int rt){

    if(L <= l && r <= R)  return maxv[rt];

    int m = (l + r) >> 1;

    int ans = -INF;

    if(L <= m)  ans = Max(ans, query(L, R, lson));

    if(R > m)   ans = Max(ans, query(L, R, rson));

    return ans;

}

int main(){

    while(scanf("%d %d", &n, &m) == 2){

        build(1, n, 1);

        char s[5];

        int x, y;

        while(m--){

            scanf("%s", s);

            if(s[0] == 'Q'){

                scanf("%d %d", &x, &y);

                printf("%d\n", query(x, y, 1, n, 1));

            }

            else{

                scanf("%d %d", &x, &y);

                update(x, y, 1, n, 1);

            }

        }

    }

    return 0;

}