Tang Seng went through 81 hardships in learning scriptures from the West, including 3 hardships alone, 77 hardships with Sun Wukong, 65 hardships with Zhu Bajie, 62 hardships with Monk Sha, and Sun Wukong and Zhu Bajie at the same time. Overcome 64 hardships together, and 61 hardships with Monkey King and Monk Sha, and 60 hardships with Zhu Bajie and Monk Sha at the same time. I would like to ask: How many hardships did the four masters and apprentices overcome together?
唐僧西天取经共经历了81难，其中单独渡过了3难，与孙悟空一起渡过了77难，与猪八戒一起渡过了65难，与沙和尚一起渡过了62难，同时与孙悟空和猪八戒一起渡过了64难，同时与孙悟空和沙和尚一起渡过了61难，同时与猪八戒和沙和尚一起渡过了60难．请问：师徒四人共同渡过的有多少难？
<gadget id="calculator">81 - 3</gadget>
<output>78</output>

<gadget id="calculator">77 + 65 + 62</gadget>
<output>204</output>

<gadget id="calculator">64 + 61 + 60</gadget>
<output>185</output>

<gadget id="calculator">204 - 185</gadget>
<output>19</output>

<gadget id="calculator">78 - 19</gadget>
<output>59</output>

<result>59</result>