LOGICAL LEAP
LEAP(NY) = MOD(NY,4).EQ.0 .AND. (NY.NE.0 .OR. MOD(NY00,400).EQ.0)
IF (NM.EQ.2 .AND. LEAP(NY)) ND = 29
IF (ND.EQ.29 .AND. NM.EQ.2 .AND. LEAP(NY)) GO TO 20
IF (NM.EQ.2 .AND. LEAP(NY)) ND = ND + 1