program kadai
	implicit none

	integer  ::  a(2)
    character(len=50)  ::  c
    read(*,*) a
    read(*,*) c

	c(a(2):a(2))=char(ichar(c(a(2):a(2)))+32)

	write(*,'(a)') trim(c)
    stop
    
end program kadai