Converting character to Numeric date

[deleted_user]

I have a bunch of data with the dates in years, for example,
1921-22,
1922-23,
1923-24.
i tried to convert them to the numeric year which will only show the first 4 numeric # as the year, for example, the date should be like,
1921,
1922,
1923.
i used input(substr(year,1,4),f4.0);
it's saying Statement is not valid or it is used out of proper order.
thanks,
Y

[Patrick]

input(substr(year,1,4),4.);