program paradox;
var n, i, j:integer;
S: array[1..325] of string;
A,B,SY: array [1..325] of char;
nodo : array[1..26] of integer;
lettere : array[1..26,1..26] of boolean;
recStack, visited : array [1..26] of boolean;
risposta: string;
ciclo : boolean;
function isCyclic (u :integer) : boolean;
var v :integer;
begin
if recStack[u] then begin isCyclic:=true; ciclo:=true; exit; end;
if visited[u] then isCyclic:=false;
visited[u]:=true;
recStack[u]:=true;
for v:=1 to 26 do if (lettere[u,v] = true) then if isCyclic(v) then isCyclic:=true;
recStack[u]:=false;
isCyclic:=false;
end;
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
for j:=1 to 26 do lettere[i, j]:=false;
for i:=1 to 26 do visited[i]:=false;
for i:=1 to 26 do recStack[i]:=false;
for i:=1 to N do
begin
if SY[i]='<' then lettere[ord(A[i])-96, ord(B[i])-96] := true
else if SY[i]='>' then lettere[ord(B[i])-96, ord(A[i])-96] :=true;
end;
for i:=1 to 26 do nodo[i]:=0;
for i:=1 to N do begin nodo[ord(A[i])-96]:=nodo[ord(A[i])-96]+1; nodo[ord(B[i])-96]:=nodo[ord(B[i])-96]+1; end;
for i:=1 to 26 do
if (nodo [i]<>0) then begin
if (visited[i]=false) and (isCyclic(i)) then ciclo:=true
else if (visited[i]=false) and (isCyclic(i)=false) then ciclo:=false; end;
if ciclo=true then risposta:=':('
else risposta:=':)';
writeln(risposta);
end.
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