Move input of date higher

Because we are going to extract the rest of the script below into a
function.

Inst_eddies/inst_eddies_in.py

@@ -26,6 +26,8 @@ argparser.add_argument("file", nargs = "+",
 argparser.add_argument("-b", "--bbox", nargs=4, type = float,
                        metavar = ("xmin", "xmax", "ymin", "ymax"))
 args = argparser.parse_args()
+d = input("Enter first date (integer value):")
+d = int(d)
 inst_eddies_exe = "@CMAKE_CURRENT_BINARY_DIR@/inst_eddies"
 
 if not os.access(inst_eddies_exe, os.X_OK):
@@ -36,8 +38,6 @@ if os.access("main_nml.txt", os.R_OK):
 else:
     sys.exit('"main_nml.txt" not found')
 
-d = input("Enter first date (integer value):")
-d = int(d)
 nco_instance = nco.Nco()
 
 for orient in ["cyclo", "anti"]: