this is one of the longest projects that don't crash on scratch. the total memory this project uses is about 4 GB, so it should run successfully assuming you have that amount of RAM (larger amounts aren't really feasible). the total amount of time it takes before it terminates is 200000^(2500*200000) = 6.791×10^2650514997 seconds. have fun! :)
it's possible to make it longer by having longer strings, but in that case there's a risk of the machine eventually running out of memory