user: 请将这段汇编代码片段转换成等效的C代码：

```asm
<main>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r14
  push   %r13
  push   %r12
  push   %rbx
  sub    $0x10,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,-0x28(%rbp)
  xor    %eax,%eax
  lea    -0x2c(%rbp),%rdx
  lea    -0x30(%rbp),%rsi
  lea    D19(%rip),%rdi
  call   <scanf@plt>
  mov    -0x30(%rbp),%eax
  add    $0x1,%eax
  cltq
  add    $0xf,%rax
  mov    %rax,%rcx
  and    $0xfffffffffffffff0,%rcx
  and    $0xfffffffffffff000,%rax
  mov    %rsp,%rdx
  sub    %rax,%rdx
L97:
  cmp    %rdx,%rsp
  je     L72
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L97
L72:
  mov    %rcx,%rax
  and    $0xfff,%eax
  sub    %rax,%rsp
  test   %rax,%rax
  je     L60
  orq    $0x0,-0x8(%rsp,%rax,1)
L60:
  mov    %rsp,%r13
  mov    -0x2c(%rbp),%ecx
  lea    0x1(%rcx),%eax
  cltq
  lea    0xf(%rax),%rdx
  mov    %rdx,%rdi
  and    $0xfffffffffffffff0,%rdi
  and    $0xfffffffffffff000,%rdx
  mov    %rsp,%rsi
  sub    %rdx,%rsi
L9:
  cmp    %rsi,%rsp
  je     L78
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L9
L78:
  mov    %rdi,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  test   %rdx,%rdx
  je     L94
  orq    $0x0,-0x8(%rsp,%rdx,1)
L94:
  mov    %rsp,%r12
  add    $0xf,%rax
  mov    %rax,%rsi
  and    $0xfffffffffffffff0,%rsi
  and    $0xfffffffffffff000,%rax
  mov    %rsp,%rdx
  sub    %rax,%rdx
L26:
  cmp    %rdx,%rsp
  je     L133
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L26
L133:
  mov    %rsi,%rax
  and    $0xfff,%eax
  sub    %rax,%rsp
  test   %rax,%rax
  je     L115
  orq    $0x0,-0x8(%rsp,%rax,1)
L115:
  mov    %rsp,%rbx
  movslq %ecx,%rcx
  movb   $0x0,(%rsp,%rcx,1)
  mov    %r13,%rsi
  lea    D14(%rip),%r14
  mov    %r14,%rdi
  mov    $0x0,%eax
  call   <scanf@plt>
  mov    %r12,%rsi
  mov    %r14,%rdi
  mov    $0x0,%eax
  call   <scanf@plt>
  mov    -0x30(%rbp),%edi
  test   %edi,%edi
  jle    L12
  lea    -0x1(%rdi),%esi
  not    %rsi
  mov    $0x0,%eax
  movslq -0x2c(%rbp),%rcx
  add    %rbx,%rcx
  movslq %edi,%rdx
  add    %rdx,%r13
L135:
  movzbl -0x1(%r13,%rax,1),%edx
  mov    %dl,-0x1(%rcx,%rax,1)
  sub    $0x1,%rax
  cmp    %rsi,%rax
  jne    L135
L12:
  mov    -0x2c(%rbp),%edx
  sub    %edi,%edx
  mov    %edx,%eax
  sub    $0x1,%eax
  js     L41
  movslq %eax,%rcx
  lea    (%rax,%rdi,1),%esi
  movslq %esi,%rsi
  movslq %edx,%rdx
  sub    %rdx,%rsi
  lea    (%r12,%rsi,1),%rdi
  add    %rbx,%rsi
L23:
  movsbl 0x1(%rdi,%rcx,1),%eax
  movsbl 0x1(%rsi,%rcx,1),%edx
  sub    %edx,%eax
  add    $0x1a,%eax
  movslq %eax,%rdx
  imul   $0x4ec4ec4f,%rdx,%rdx
  sar    $0x23,%rdx
  mov    %eax,%r8d
  sar    $0x1f,%r8d
  sub    %r8d,%edx
  imul   $0x1a,%edx,%edx
  sub    %edx,%eax
  add    $0x61,%eax
  mov    %al,(%rbx,%rcx,1)
  sub    $0x1,%rcx
  test   %ecx,%ecx
  jns    L23
L41:
  mov    %rbx,%rdi
  call   <puts@plt>
  mov    -0x28(%rbp),%rax
  sub    %fs:0x28,%rax
  jne    L83
  mov    $0x0,%eax
  lea    -0x20(%rbp),%rsp
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %rbp
  ret
L83:
  call   <__stack_chk_fail@plt>
```

tool_calls: name: read_data
arguments: label: D19
datatype: string
name: read_data
arguments: label: D14
datatype: string

tool: D19: %d %d

tool: D14: %s

assistant: ```c
int main() {
  int n, m;
  scanf("%d %d", &n, &m);
  char last[n + 1], encrypted[m + 1], plain[m + 1];
  plain[m] = 0;
  scanf("%s", last);
  scanf("%s", encrypted);
  for (int i = 0; i < n; i++)
    plain[m - 1 - i] = last[n - 1 - i];
  for (int i = m - n - 1; i >= 0; i--)
    plain[i] = (char)(((26 + (((encrypted[i + n]) - 'a') - ((plain[n + i]) - 'a'))) % 26) + 'a');
  printf("%s\n", plain);
  return 0;
}
```