If previous character is 1 then words that can be formed are K ( 11 ) , L ( 12 ) , M ( 13 ) , N ( 14 ) O ( 15 ) , P ( 16 ) , Q ( 17 ) , R ( 18 ) , S ( 19 )
if ( s [ i - 1 ] == ' ' ) second = ( second + 9 * first ) % M ;