Chemical Kinetics Part 2

A⟶B
The molecule A changes into its isomeric form B by following a first order kinetics at a temperature of 1000 K . If the energy barrier with respect to reactant energy for such isomeric transformation is 191.48 kJ‌mol−1 and the frequency factor is 1020, the time required for 50% molecules of A to become B is ______ picoseconds (nearest integer). [R=8.314 J K-1 mol−1]