#/***********************************************************
#    postfix.rb -- 後置記法
#***********************************************************/

def readch  # １文字を読む. 空白は読み飛ばす. 
    begin 
        if (($ch = $stdin.getc) == nil); $ch = ?\0; return ; end
    end while ($ch == ?\s || $ch == ?\t)
end

def factor  # 因子 
    if ($ch == ?\() 
        readch();  expression()
        if ($ch == ?\)); readch(); else; print "?" ; end
    elsif (($ch.chr =~ /[[:graph:]]/) != nil) 
        print($ch.chr);  readch()
    else print('?'); end
end

def term # 項 
    factor()
    while (true)
        if ($ch == ?*) 
            readch();  factor();  print('*')
        elsif ($ch == ?/) 
            readch();  factor();  print('/')
        else; break; end
    end
end

def expression  # 式 
    term()
    while (true)
        if ($ch == ?+) 
            readch();  term();  print('+')
        elsif ($ch == ?-) 
            readch();  term();  print('-')
        else; break; end
    end
end

begin 
    readch(); expression()
    while ($ch != ?\n && $ch != ?\0) 
        print('?');  readch()
    end
    print("\n")
end while ($ch != ?\0)

exit 0