.\" US letter dimensions
.device papersize=8.5i,11i
.
.\" Calculate line length with PO
.if (\\n[PO] == 0) \{\
.   \" If PO not defined, set to 1i
.   nr PO 1i
.\}
.
.\" Define line and header/footer
.\" lengh as such
.nr LL \\n[PO]*-2+8.5i
.nr LT \\n[PO]*-2+8.5i