//218ms
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <vector>
#include <set>
using namespace std;
const int maxn=1000100;
set <int> s;
struct node
{
    int lazy;
    int left;
    int right;
    int value;
    int mid()
    {
        return (left+right)>>1;
    }
}tree[3*maxn];
int n;
void built(int n,int left,int right)
{
    tree[n].lazy=0;
    tree[n].left=left;
    tree[n].right=right;
    if(left==right)
    {
        tree[n].value=2;
        return;
    }
    int mid=tree[n].mid();
    built(n<<1,left,mid);
    built(n<<1|1,mid+1,right);
    tree[n].value=2;
}
void pushdown(int rt)
{
    if(tree[rt].lazy)
    {
        tree[rt<<1].lazy=tree[rt<<1|1].lazy=tree[rt].lazy;
        tree[rt<<1].value=tree[rt].value;
        tree[rt<<1|1].value=tree[rt].value;
        tree[rt].lazy=0;
    }
}
void update(int rt,int L,int R,int val)
{
    if(L<=tree[rt].left&&tree[rt].right<=R)
    {
        tree[rt].lazy=1;
        tree[rt].value=val;
        return ;
    }
    pushdown(rt);//向下更新一次
    int mid=tree[rt].mid();
    if(L<=mid)
        update(rt<<1,L,R,val);
    if(R>mid)
        update(rt<<1|1,L,R,val);
    if(tree[rt<<1].value==tree[rt<<1|1].value)
    tree[rt].value=tree[rt<<1].value;
    else
    tree[rt].value=0;
}
void quarry(int rt,int left,int right)//查询
{
    if(left>tree[rt].right||right<tree[rt].left)
    {
        return;
    }
    if(tree[rt].value)
    {
        s.insert(tree[rt].value);
        return;
    }
    quarry(rt<<1,left,right);
    quarry(rt<<1|1,left,right);
}
int main()
{
    int m,x,y,z;
    while(~scanf("%d%d",&n,&m)&&n+m)
    {
        built(1,1,n);
        char c;
        while(m--)
        {
             cin>>c;
            if(c=='P')
            {
                scanf("%d%d%d",&x,&y,&z);
                update(1,x,y,z);
            }
            else
            {
                scanf("%d%d",&x,&y);
                s.clear();
                quarry(1,x,y);
                set<int>::iterator it;
                for(it=s.begin();it!=s.end();it++)
                {
                    if(it==s.begin())
                    printf("%d",*it);
                    else
                    printf(" %d",*it);
                }
                printf("\n");
            }
        }
    }
    return 0;
}