program main
    implicit none
    integer::t,x(0:100),i,j
    read*,t
    do i=1,t
        read*,x(i)
    end do
    x(0)=0
    do i=1,t
        if(abs(x(i)-x(i-1))/=1)then
            print*,"F"
            return
        end if
    end do
    print*,"T"
end program