program xxxx;
var z,n,i,m1,m2,y,x,i1,i2,j:longint;
    a:array[1..1050] of char;
begin
  assign(input,'beads.in');
  reset(input);
  assign(output,'beads.out');
  rewrite(output);
  readln(n);
  for i:=1 to n do
    begin
      read(a[i]);
      a[i+n]:=a[i];
      a[i+n+n]:=a[i];
    end;
  for i:=1+n to n+n do
    begin
      m1:=0;m2:=0;x:=0;y:=0;
      i1:=i;i2:=i+1;
      if a[i+1]<>'w' then
        i2:=i+1
      else
        repeat
          begin
            inc(i2);
            inc(m2);
          end
        until
          a[i2]<>'w';
      for j:=0 to n-1 do
        begin
        if (a[i2+j]='w')or(a[i2+j]=a[i2]) then
          inc(m2)
        else
          begin
            if m2>y then
              begin
                y:=m2;
               // m2:=0;
              end;
            break;
          end;
        end;
      if a[i]<>'w' then
        i1:=i
      else
        repeat
          begin
            dec(i1);
            inc(m1);
          end
        until
          a[i1]<>'w';
      for j:=0 to n-1 do
        begin
        if (a[i1-j]='w')or(a[i1-j]=a[i1]) then
          inc(m1)
        else
          begin
            if m1>x then
              begin
                x:=m1;
                //m1:=0;
              end;
            break;
          end;
        end;
      if x+y>z then
        z:=x+y;
    end;
  if z>n then
    write(n)
  else
  write(z);
  close(input);
  close(output);
end.