3. The information processing apparatus according to claim 1 , wherein the procedure further includes extracting words or phrases included in the formats specified by the first filter information, and generating the second filter information based on appearances of the extracted words or phrases.
3. The information processing apparatus according to claim 1 , wherein the procedure further includes extracting words or phrases included in the formats specified by the first filter information, and generating the second filter information based on appearances of the extracted words or phrases. 4. The information processing apparatus according to claim 3 , wherein the generating includes extracting words and phrases included in the formats specified by the first filter information, calculating weights for the extracted words based on the appearances of the extracted words, and calculating weights for the extracted phrases based on the weights for the extracted words.