/in/foo.c: In function 'ax':
/in/foo.c:5:8: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if(n>2&&!(n%2==1)||n<2)
     ~~~^~~~~~~~~~~
/in/foo.c: In function 'main':
/in/foo.c:19:7: warning: implicit declaration of function 'cj' [-Wimplicit-function-declaration]
    if(cj(t))
       ^~
/tmp/ccmxyv3A.o: In function `main':
foo.c:(.text.startup+0x4b): undefined reference to `cj'
collect2: error: ld returned 1 exit status