class="bi x0 y0 w0 h1"
class="bi x0 y0 w0 h1"
class="bi x0 y0 w0 h1"
N
M
N’=N+m
M’
N
M
N’=N+m
M’
N
M
N’=N+(m-1)
M’
N
M
N’=N+(m-1)
M’
N
M
N’=N+1
M’
N
M
N’=N+1
M’
class="bi x0 y0 w0 h1"