Bump function with integral $1$ and value $1$ at zero

How can i contruct a smooth bump function $F$ on $\Bbb{R}^n$ such that $F(0)=1$ and with integral $1$?

I have tried to manipulate the function $f(x)=e^{-\frac{1}{x^2}}$ if $x>0$ and $f(x)=0$ if $x \leq 0$, ta find a such function $g$, but i only get one of the 2 conditions.

Then, of course,we can define $F(x)=g(x_1)* g(x_2)***g(x_n)$ on $\Bbb{R}^n$

Thank you in advance.