Confuse the calculation of the shflux

[shiyf]

I have down load the 3-hours step data of slhf, ssr,str,strd (W m-2 s)from ECMWF,

if the shflux(W m-2)= -(ssr+str+sshf+slhf) / (3*3600)?

could you help me, thank you very much!