foo.c: In function 'main':
foo.c:7:5: warning: ignoring return value of 'fgets', declared with attribute warn_unused_result [-Wunused-result]
    7 |     fgets(str1, sizeof(str1), stdin);
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.c:9:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    9 |     scanf("%d%d", &k, &l);
      |     ^~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/string.h:495,
                 from foo.c:2:
In function 'strcat',
    inlined from 'Delete' at foo.c:25:5:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:128:10: warning: '__builtin_strcat' accessing 4611686018427387905 or more bytes at offsets 0 and [-4611686018427387904, 4611686018427387903] may overlap 1 byte at offset [0, 9223372036854775807] [-Wrestrict]
  128 |   return __builtin___strcat_chk (__dest, __src, __bos (__dest));
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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