If the sum of first 11 terms of an A.P., \(a_{1},a_{2},a_{3},\ldots.\). is \(0\left( a_{1} \neq 0 \right)\), then the sum of the A.P., \(a_{1},a_{3},a_{5},\ldots,a_{23}\) is \(ka_{1}\), where \(k\) is equal to