The total length of the three railways A, B and C is 1191 kilometers. The length of railway A is 189 kilometers less than twice that of railway B. The length of railway B is 8 kilometers less than that of railway C. Find the length of railway A.
甲、乙、丙三条铁路共长1191千米，甲铁路长比乙铁路的2倍少189千米，乙铁路长比丙铁路少8千米，求甲铁路的长．
<gadget id="calculator">1_191 - 8</gadget>
<output>1_183</output>

<gadget id="calculator">189 + 1_183</gadget>
<output>1_372</output>

<gadget id="calculator">2 + 1 + 1</gadget>
<output>4</output>

<gadget id="calculator">1_372 / 4</gadget>
<output>343</output>

<gadget id="calculator">2 * 343</gadget>
<output>686</output>

<gadget id="calculator">686 - 189</gadget>
<output>497</output>

<result>497</result>