# [Python 2], <s>104</s> 94 bytes

<!-- language-all: lang-python -->

    n=input()
    for i in range(n):s=n-i;print' '*(s+1)+'/ '*i+'_'*(2*s+len(`n`))
    print'\/'*n+' '+`n`

[Try it online!][TIO-k9zeksgn]

Edit 1: Lol forgot I switched to python 2, saved 10 bytes

[Python 2]: https://docs.python.org/2/
[TIO-k9zeksgn]: https://tio.run/##Jcq7CoQwEEbh3qdIN5kM4q1TfBNh3cLLgPyGJBY@fTaw3eHj@DedN/qcMSv8kyxX@x2MGoUJXxybBY9xRq2TD4pEhpyN0rFQU1KFPgV6F@XaYFeszNV/XBpykPJL0ZyH9gc "Python 2 – Try It Online"