integer::N
  character(30),allocatable::A(:,:)
  character(30),parameter::nyanpass='nyanpass                      '
  integer::renge=-1,i,j
  read *,N
  allocate(A(N,N))
  read *,A

  do i=1,N
     do j=1,i-1
        if(A(i,j).ne.nyanpass) goto 100
     end do
     do j=i+1,N
        if(A(i,j).ne.nyanpass) goto 100
     end do
     if(renge.ne.-1) then
        renge = -1
        exit
     else
        renge = i
     end if
100 end do
  print '(i0)',renge
end program