foo.c: In function 'main':
foo.c:6:36: warning: unused variable 'p1' [-Wunused-variable]
    6 |  int n,m,a,b,i,j,t,k=0,q=0,p=0,f=0,p1;
      |                                    ^~
foo.c:9:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    9 |  scanf("%d%d",&n,&m);
      |  ^~~~~~~~~~~~~~~~~~~
foo.c:18:4: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   18 |    scanf("\n%c",&zhiling);
      |    ^~~~~~~~~~~~~~~~~~~~~~
foo.c:21:4: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   21 |    scanf("%d%d",&a,&b);
      |    ^~~~~~~~~~~~~~~~~~~
foo.c:40:4: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   40 |    scanf("%d",&a);
      |    ^~~~~~~~~~~~~~

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