class Converter : IConvert
        {
            int fromString(string value, string baseStr)
            {
                int[] values = new int[ 128 ];
                int n =  0 ;
                for (int i =  0 ; i < baseStr.Length; i++)
                    if (i %  2  ==  0 )
                    {
                        values[(byte)baseStr[i]] = n++;
                    }
                int ret =  0 ;
                for (int i =  0 ; i < value.Length; i++)
                {
                    ret = ret * n + values[(byte)value[i]];
                }
                return ret;
            }
            string toString(int value, string baseStr)
            {
                string ret = "";
                string[] alphabet = baseStr.Split(',');
                int n = alphabet.Length;
                do
                {
                    ret = alphabet[value % n] + ret;
                    value /= n;
                } while (value >  0 );
                return ret;
            }
            public string Convert(string value, string fromBase, string toBase)
            {
                return toString(fromString(value, fromBase), toBase);
            }
        }