In $\mathrm{HCHO}$, there are $\mathrm{x}$ non-bonding electron pairs, y$\mathrm{\sigma }$-bonds and z$\mathrm{\pi }$-bonds.The sum of $\mathrm{x},\mathrm{y}$ and z is__________

In structure of HCHO(Formaldehyde) there is

non-bonding=2(x); sigma bond=3(y) ; pi bonds=1(z)

x+y+z=6

Hence, correct answer is:6