Basic string concatenation.
abbbcccccccccXXXXdddddddddddddddddddddddddddXXXXabbbcccccccccXXXXdddddddddddddddddddddddddddXXXXeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeabbbcccccccccXXXXdddddddddddddddddddddddddddXXXXeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeabbbcccccccccXXXXdddddddddddddddddddddddddddXXXXabbbcccccccccXXXXdddddddddddddddddddddddddddXXXXeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeabbbcccccccccXXXXdddddddddddddddddddddddddddXXXXeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeaabbbcccccccccXXXXdddddddddddddddddddddddddddXXXXabbbcccccccccXXXXdddddddddddddddddddddddddddXXXXeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeabbbcccccccccXXXXdddddddddddddddddddddddddddXXXXeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeXXXX