The number of a 5 Euro banknote starts with a land code of two letters, followed by 10 digits. For example, the land code UE stands for France. If we replace the letters of the alphabet by their two-digit positions in the alphabet (e.g. UE is replaced by 21 05), we find a number of in total 14 digits. It appears that the obtained number always equals 7 (mod 9). Is this code 1-error correcting? If so, why? If not, give an example of a number of a bank note that has one error in it that cannot be corrected.