View Compilation Error

0_0_18768926_2154.c: In function 'main':
0_0_18768926_2154.c:7:41: error: 'B' undeclared (first use in this function)
     while(scanf("%d%d",&a,&b)==2&&a!=0||B!=0)
                                         ^
0_0_18768926_2154.c:7:41: note: each undeclared identifier is reported only once for each function it appears in