We will implement Lambert's W-function, which is the inverse of f(x)= x*e^x
Let x=e^t
Then take the natural logarithm of both the sides to obtain
100*ln10 = t*e^t
=> t = W(100*ln10)
=> x = e^(W(100*ln10))
We get x= 56.961248432... using Wolfram Alpha.