Though Yueyue and Lele are brothers , they are very different.
For example, Yueyue is very hard in study, especially in writing compositions. To make the composition looks nice , he will not use the same word twice. While Lele is very lazy, and he sometimes copys his brother's homework.
Last week, their teacher asked them to write a composition named "My Mother", they handed the same composition. The teacher was very angry , but Lele just answered "We have the same mother , why should our compositions be different ?"
Now,the teacher is asking Yueyue and Lele to write the compositions again, and he wants to calculate the length of longest common subsequence of words occuring in the two compositions. Can you help him ?