A, B, and C water 100 pots of flowers at the same time. It is known that A has watered 78 pots, B has watered 68 pots, and C has watered 58 pots. How many pots have all three of them watered at least?
甲乙丙同时给100盆花浇水，已知甲浇了78盆，乙浇了68盆，丙浇了58盆，那麽三人都浇过的至少有多少盆？
<gadget id="calculator">78 + 68 + 58</gadget>
<output>204</output>

<gadget id="calculator">100 * 2</gadget>
<output>200</output>

<gadget id="calculator">204 - 200</gadget>
<output>4</output>

<result>4</result>