t$1=$ n $==0$

t$2=$ n $==1$

t$3=$ t$1||$ t$2$

if t$3$ goto L$1$

result $=1$

i $=2$

L$2$: t$4=$ i $<=$ n

if t$4$ goto L$3$

goto L$4$

L$3$: result $=$ result $*$ i

i $=$ i $+1$

goto L$2$

L$4$: return result

L$1$: return $1$

make cfg