program rice

	implicit none

	integer choice
	real p,r,m,beta

 1	write(*,*)'Beta?'
	read(*,*)beta
	write(*,*)'Average annual rainfall in mm?'
	read(*,*)m
 2	write(*,*)'Rainfall rate in mm/hr?'
	read(*,*)r

 10	p=m/87.6*(0.03*beta*exp(-0.03*r)+0.2*(1-beta)*
     .  (exp(-0.258*r)+1.86*exp(-1.63*r)))
	write(*,*)
	write(*,*)'Rainfall rate ',r,' will be exceeded ',p,
     .  ' percent of the time'
	write(*,*)'This is ',p/100*365*24,' hours per year'
	write(*,*)
	write(*,*)'0=quit, 1=change beta, 2=change m, 3=change r'
	write(*,*)'3=change r, 4=change all'
	
	read(*,*)choice
	if (choice.eq.4) goto 1
	if (choice.eq.3) goto 2
	if (choice.eq.2) then
	  write(*,*)'Average annual rainfall in mm?'
	  read(*,*)m
	  goto 10
        endif
	if (choice.eq.1) then
	  write(*,*)'Beta?'
	  read(*,*)beta
	  goto 10
        endif
	end