var a,b,c,d,x1,x2:Real;
begin
writeln('a and b and c');
readln(a,b,c);
d:= b*b -4*a*c;
if a=0 then
begin
if b=0 then
begin
if c=0 then
WriteLn('ptvsn')
else WriteLn('ptvn');
end
else
x1:=-c/b;
WriteLn('x=',x1);
end;
if d < 0 then
begin
writeln('vonghiem');
readln;
end;
if d > 0 then
begin
x1:=(-b-sqrt(d))/(2*a);
x2:=(-b+sqrt(d))/(2*a);
Writeln('x1=',x1:2:1,'x2=',x2:2:1);
readln;
end;
if d =0 then
begin
x1:= (-b)/(2*a);
writeln('x1=x2=',x1:2:1);
readln;
end;
readln
end.