/in/foo.c: In function 'main':
/in/foo.c:10:8: warning: unknown escape sequence: '\040'
  scanf("%d\ %d",&b1,&a1);
        ^~~~~~~~
/in/foo.c:11:8: warning: unknown escape sequence: '\040'
  scanf("%d\ %d",&b2,&a2);
        ^~~~~~~~
/in/foo.c:32:9: warning: unknown escape sequence: '\040'
  printf("%d\ %d",l,k);
         ^~~~~~~~