program Project2;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var z:set of char;
  {ch,ch1:char;}
  i,j:integer;
  b,t:boolean;
  a:array[0..501]of char;
begin
assign(input,'text.in');
reset(input);
 assign(output,'text.out');
rewrite(output);
i:=0;
{z:=z+['.']+['?']+['!'];}
b:=false;
t:=false;
while not eoln do
begin
inc(i);
read(a[i]);
end;
for j:=1 to i do
begin
{read(ch);}
{if i=0 then begin if not(ch in['a'..'z'])then i:=1 else i:=2; end  else
if i=1 then begin if (not(ch in['A'..'Z'])) then else i:=2; end else
if (ch='.')or(ch='!')or(ch='?')then i:=0;
if i=2 then begin if ch in['A'..'Z']then write(chr(ord(ch)+32))else
if ch in['a'..'z'] then write(chr(ord(ch)-32)) end else write(ch);
{write(ord('A'),' ',ord('a'));}
if (a[j] in ['A'..'Z'])and(a[j+1] in ['A'..'Z'])then b:=true;
if (a[j+1] in ['A'..'Z'])and(a[j] in ['a'..'z'])then
begin b:=true; if (a[j-1]in['A'..'Z'])or(a[j-1]in ['a'..'z']) then t:=true;end;
if (b)and(not(t))and((a[j]in ['A'..'Z'])or(a[j]in ['a'..'z'])) then begin if a[j] in['A'..'Z']then write(chr(ord(a[j])+32))else
if a[j] in['a'..'z'] then write(chr(ord(a[j])-32))end  else write(a[j]);
if t then t:=false;
{ch1:=ch;}
end;
close(input);


close(output);
end.