#include <bits/stdc++.h>

#define lson l, m, rt<<1

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

using namespace std;

const int MAXN = 200008;

int maxs[MAXN<<2];

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

{

    if(l == r)

    {

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

        return;

    }

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

    build(lson);

    build(rson);

    maxs[rt] = max(maxs[rt<<1], maxs[rt<<1|1]);

}

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

{

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

    int ret = 0;

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

    if(L <= m) ret = max(ret, query(L, R, lson));

    if(R > m) ret = max(ret, query(L, R, rson));

    return ret;

}

void updata(int p, int news, int l, int r, int rt)

{

    if(l == r)

    {

        maxs[rt] = news;

        return;

    }

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

    if(p <= m) updata(p, news, lson);

    else updata(p, news, rson);

    maxs[rt] = max(maxs[rt<<1], maxs[rt<<1|1]);

}

int main()

{

//    freopen("in.txt", "r", stdin);

    int n,k;

    while(~scanf("%d%d", &n, &k))

    {

        build(1, n, 1);

        while(k--)

        {

            char s[5];

            scanf("%s", s);

            int a,b;

            scanf("%d%d", &a, &b);

            if(s[0] == 'Q') printf("%d\n", query(a, b, 1, n, 1));

            else updata(a, b, 1, n, 1);

        }

    }

    return 0;

}