/in/foo.c: In function 'main':
/in/foo.c:46:34: error: 'n3' undeclared (first use in this function)
     scanf("%d %d %d", &n1, &n2, &n3);
                                  ^~
/in/foo.c:46:34: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:57:26: error: 'a3' undeclared (first use in this function)
     nb2 = Unique(a1, n1, a3, n3, b2);
                          ^~