foo.c: In function 'main':
foo.c:8:10: warning: unused variable 'n' [-Wunused-variable]
    8 |  int X,i,n=0,num;
      |          ^
foo.c:8:8: warning: unused variable 'i' [-Wunused-variable]
    8 |  int X,i,n=0,num;
      |        ^
foo.c:9:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    9 |  scanf("%d%d%d",&X,&M,&N);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务