foo.c: In function 'main':
foo.c:6:2: warning: implicit declaration of function 'scanf_s'; did you mean 'scanf'? [-Wimplicit-function-declaration]
    6 |  scanf_s("%d", &M);
      |  ^~~~~~~
      |  scanf
foo.c:15:13: warning: format '%d' expects argument of type 'int', but argument 2 has type 'long int' [-Wformat=]
   15 |    printf("%d %d\n", i, n - 1);
      |            ~^        ~
      |             |        |
      |             int      long int
      |            %ld
foo.c:15:16: warning: format '%d' expects argument of type 'int', but argument 3 has type 'long int' [-Wformat=]
   15 |    printf("%d %d\n", i, n - 1);
      |               ~^        ~~~~~
      |                |          |
      |                int        long int
      |               %ld
/usr/bin/ld: /tmp/cc4Kbis5.o: in function `main':
foo.c:(.text.startup+0x2e): undefined reference to `scanf_s'
collect2: error: ld returned 1 exit status

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