char letter='0';
            int openab=0;
            int openabnoc=0;
            int openacb=0;
            int sumab=0;
            int sumabnoc=0;
            int sumacb=0;
            int i;
     
            scanf("%c",&letter);
            while(letter!='.')
            {
                    if(letter=='a')
                    {
                            openab++;
                            openabnoc++;
                    }
                    if(letter=='c'&&openabnoc!=0)
                    {
                            openabnoc--;
                            openacb++;
                    }
                    if(letter=='b'&&openabnoc!=0)
                    {
                            sumabnoc++;
                    }
                    if(letter=='b'&&openab!=0)
                    {
                            for(i=1;i<=openab;i++)
                            {
                                    sumab++;
                            }
                    }
                    if(letter=='b'&&openacb!=0)
                    {
                            sumacb++;
                    }