Program srednee;

var
    a1, a2, a3: integer;

begin
    write ('Введите три числа: ');
    readln (a1, a2, a3);
    
    if ((a1<=1000) and (a2<=1000) and (a3<=1000)) and ((a1>=-1000) and (a2>=-1000) and (a3>=-1000))  then

    if (a1 = a2) or (a1 = a3) or (a2 = a3) or ((a1 = a2) and (a2 = a3)) then
        writeln('Error')
    else
        if ((a1 > a2) and (a1 < a3)) or ((a1 < a2) and (a1 > a3)) then
            writeln(a1)
        else
            if ((a2 > a1) and (a2 < a3)) or ((a2 < a1) and (a2 > a3)) then
                writeln(a2)
            else
                writeln(a3)
                
                else
                    writeln('Error')

end.