clear
//
//
//

//Variable declaration    
M=120;     //atomic mass
N=6.023*10^23;      //avagadro number
n=2;
g=20;       //mass(gm)

//Calculations
u=n*M/N;     
nu=g/u;       //number of unit cells

//Result
printf("\n number of unit cells is %0.3f *10^22",nu/10^22)