program Coulomb
real,parameter::e=1.6e-19,eps=8.86e-12,pi=3.1416
real::r,phi
integer::z
print*,"Please enter the distance in meters:(r)"
read*,r
print*,"Please enter the particle charge: (z)"
read*,z
phi=(z*e)/(4*pi*eps*r)
print*,"The Columb potential is ",phi
end program Coulomb