program happya;
  type
    arry=record
      key,num:longint;
    end;
  var
    i,j,n,t,total,ans,x,y,w,m,v:longint;
    tree:array[0..100000*5] of arry;
    ch:char;
  procedure change(x,l,r,p,v:longint);
    var
        m:longint;
    begin
      if (l>p)or(r<p) then exit;
      if l=r then
        begin
          tree[x].key:=tree[x].key+v;
          tree[x].num:=j;
          exit;
        end;
        m:=(l+r) div 2;
        if p<=m then change(x+x,l,m,p,v);
        if p>m then change(x+x+1,m+1,r,p,v);
        if tree[2*x].key>=tree[2*x+1].key then
          begin
            if tree[x].key<tree[2*x].key then
              tree[x]:=tree[2*x];
          end
        else
          if tree[x].key<tree[2*x+1].key then
            tree[x]:=tree[2*x+1];
    end;
  function query(root,l,r:longint):longint;
    var
      m1,m2,m:longint;
    begin
      if (r<x)or(l>y) then exit(0);
      if (l>=x)and(r<=y) then exit(root);
      m:=(l+r) div 2;
      m1:=query(root*2,l,m);
      m2:=query(root*2+1,m+1,r);
      if tree[m1].key>=tree[m2].key then exit(m1)
                                   else exit(m2);
    end;
  procedure change1(x,l,r,p,v:longint);
    var
        m:longint;
    begin
      if (l>p)or(r<p) then exit;
      if l=r then
        begin
          tree[x].key:=v;
          exit;
        end;
        m:=(l+r) div 2;
        if p<=m then change1(x+x,l,m,p,v);
        if p>m then change1(x+x+1,m+1,r,p,v);
        if tree[2*x].key>=tree[2*x+1].key then
              tree[x]:=tree[2*x]
        else
            tree[x]:=tree[2*x+1];
    end;
  begin
    assign(input,'happya.in');reset(input);
    assign(output,'happya.out');rewrite(output);
    fillchar(tree,sizeof(tree),0);
    readln(n,m);
    for i:=1 to m do
      begin
        read(ch);
        if ch='I' then
          begin
            readln(x,y,v);
            for j:=x to  y do
             change(1,1,n,j,v)
          end
        else
          begin
            readln(x,y);
            t:=tree[query(1,1,n)].num;
            writeln(tree[query(1,1,n)].key);
            change1(1,1,n,t,0);
          end;
      end;
    close(input);close(output);
  end.