program INTEGERCOUNT

implicit none

INTEGER :: n

PRINT *, "Enter a positive integer n"

READ *, n

PRINT *, n, " contains ", IntCount(n), " digits."

CONTAINS

RECURSIVE FUNCTION IntCount(n) Result (IC)

INTEGER :: IC, k

INTEGER, INTENT(IN) :: n

k=n/10

IF (k==0) THEN

IC=1

ELSE

IC=1+IntCount(k)

END IF

END FUNCTION IntCount

end program INTEGERCOUNT