enum M{M;System z;int b,i;{try{for(int[]a=new int[99];(b=(b=z.in.read())>124?49-a[i--]/97:b>122?a[++i]=1:b)>0;a[i]-=b*2-97)if(i<1)z.out.write(b);}catch(Exception e){}}}