PROGRAM rps2ps
      REAL X(100000),y(10000),psi
      INTEGER I,mm 
      mm=100000
      do 10 i=1,mm                                                  
       READ(*,*,END=11) X(i),y(i)
10    continue   
11    mm=i-1
      do 25 i=1,mm
       psi=atan(sqrt(y(i)))
       write(*,*) x(i),psi
25    continue
      END