u1 n21.txt
Revert "u1 n21.txt"

This reverts commit be19d0202cf407cd168653feb5d7f7161aaf923e.
u2 n21.txt
up 2 t1.txt
up n1.txt 2
merge n1.txt
up n1.txt
up n1.txt
add n1.txt
add
a
a
fas
aa