## Editorial for COCI '16 Contest 2 #2 Tavan

**only**when stuck, and

**not to copy-paste code from it**. Please be respectful to the problem author and editorialist.

**Submitting an official solution before solving the problem yourself is a bannable offence.**

For of points, the ink is spilled over only one letter, so it is sufficient to alphabetically sort the letters that could replace it and use the one. This is a good example of a task where a simple approach can get you a large number of points.

There are multiple solutions where it is possible to obtain all points. One of them is to convert the number to a number in a numerical system where the base is . For easier implementation, we pad the number with leading zeros so that the total number of digits is . Let the digits of the new number be , respectively. Then the unknown letter must be replaced by the letter from the sorted order of letters that could potentially replace the letter (the letters in the sorted order are 0-indexed).

The time complexity of this solution is .

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