Xiaoxiao is playing on a ladder. If you take 4 steps in each step, you will have 3 steps left in the end; if you take 5 steps in each step, you will have 4 steps in the end; Question: What is the minimum number of steps in this ladder?
笑笑在一个阶梯上玩，如果每步跨4阶，最后余3阶；如果每步跨5阶，最后余4阶；如果每步跨6阶，最后余5阶．请问：这个阶梯最少共有多少阶？
<gadget id="calculator">60 - 1</gadget>
<output>59</output>

<result>59</result>