program paradox;
var n, i, count:integer;
    S: array[1..325] of string;
    A,B,SY: array [1..325] of char;
    lettere : array[1..26] of integer;
    risposta: string;
begin
    readln(N);
    for i:=1 to  N  do readln(S[i]);
    for i:=1 to N do begin A[i]:=S[i][1]; SY[i]:=S[i][3]; B[i]:=S[i][5];end;
    for i:=1 to 26 do lettere[i]:=0;
    for i:=1 to N do begin if SY[i]='<' then lettere[ord(A[i])-96]:=lettere[ord(A[i])-96]+1
                                        else lettere[ord(B[i])-96]:=lettere[ord(B[i])-96]+1; end;
    risposta:=':('; count:=0;
    for i:=1 to 26 do if lettere[i]=0 then count:=count+1;
    if (26-count=N) then risposta:=':('
                      else for i:=1 to 26 do if (lettere[i]<=2)  then risposta:=':)';    
    writeln(risposta);
end.

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MwphICZndDsgYgpjICZsdDsgYgphICZsdDsgYw==

3
a > b
c < b
a < c