user: 请从给定的汇编指令推导出C源代码：

```asm
<main>:
  endbr64
  sub    $0x18,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,0x8(%rsp)
  xor    %eax,%eax
  lea    0x7(%rsp),%rsi
  lea    D200(%rip),%rdi
  call   <scanf@plt>
  cmpb   $0x61,0x7(%rsp)
  je     L31
L473:
  cmpb   $0x62,0x7(%rsp)
  je     L403
L149:
  cmpb   $0x63,0x7(%rsp)
  je     L418
L309:
  cmpb   $0x64,0x7(%rsp)
  je     L184
L501:
  cmpb   $0x65,0x7(%rsp)
  je     L94
L527:
  cmpb   $0x66,0x7(%rsp)
  je     L415
L44:
  cmpb   $0x67,0x7(%rsp)
  je     L171
L100:
  cmpb   $0x68,0x7(%rsp)
  je     L154
L417:
  cmpb   $0x69,0x7(%rsp)
  je     L506
L384:
  cmpb   $0x6a,0x7(%rsp)
  je     L430
L293:
  cmpb   $0x6b,0x7(%rsp)
  je     L33
L124:
  cmpb   $0x6c,0x7(%rsp)
  je     L492
L476:
  cmpb   $0x6d,0x7(%rsp)
  je     L322
L270:
  cmpb   $0x6e,0x7(%rsp)
  je     L143
L70:
  cmpb   $0x6f,0x7(%rsp)
  je     L52
L496:
  cmpb   $0x70,0x7(%rsp)
  je     L358
L25:
  cmpb   $0x71,0x7(%rsp)
  je     L344
L328:
  cmpb   $0x72,0x7(%rsp)
  je     L42
L502:
  cmpb   $0x73,0x7(%rsp)
  je     L285
L261:
  cmpb   $0x74,0x7(%rsp)
  je     L487
L102:
  cmpb   $0x75,0x7(%rsp)
  je     L111
L314:
  cmpb   $0x76,0x7(%rsp)
  je     L8
L86:
  cmpb   $0x77,0x7(%rsp)
  je     L433
L513:
  cmpb   $0x78,0x7(%rsp)
  je     L453
L360:
  cmpb   $0x79,0x7(%rsp)
  je     L254
L180:
  cmpb   $0x7a,0x7(%rsp)
  je     L168
L438:
  mov    0x8(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L259
  mov    $0x0,%eax
  add    $0x18,%rsp
  ret
L31:
  lea    D213(%rip),%rdi
  call   <printf@plt>
  jmp    L473
L403:
  lea    D15(%rip),%rdi
  call   <printf@plt>
  jmp    L149
L418:
  lea    D231(%rip),%rdi
  call   <printf@plt>
  jmp    L309
L184:
  lea    D139(%rip),%rdi
  call   <printf@plt>
  jmp    L501
L94:
  lea    D222(%rip),%rdi
  call   <printf@plt>
  jmp    L527
L415:
  lea    D54(%rip),%rdi
  call   <printf@plt>
  jmp    L44
L171:
  lea    D88(%rip),%rdi
  call   <printf@plt>
  jmp    L100
L154:
  lea    D154(%rip),%rdi
  call   <printf@plt>
  jmp    L417
L506:
  lea    D1(%rip),%rdi
  call   <printf@plt>
  jmp    L384
L430:
  lea    D51(%rip),%rdi
  call   <printf@plt>
  jmp    L293
L33:
  lea    D269(%rip),%rdi
  call   <printf@plt>
  jmp    L124
L492:
  lea    D195(%rip),%rdi
  call   <printf@plt>
  jmp    L476
L322:
  lea    D66(%rip),%rdi
  call   <printf@plt>
  jmp    L270
L143:
  lea    D226(%rip),%rdi
  call   <printf@plt>
  jmp    L70
L52:
  lea    D39(%rip),%rdi
  call   <printf@plt>
  jmp    L496
L358:
  lea    D267(%rip),%rdi
  call   <printf@plt>
  jmp    L25
L344:
  lea    D141(%rip),%rdi
  call   <printf@plt>
  jmp    L328
L42:
  lea    D128(%rip),%rdi
  call   <printf@plt>
  jmp    L502
L285:
  lea    D98(%rip),%rdi
  call   <printf@plt>
  jmp    L261
L487:
  lea    D157(%rip),%rdi
  call   <printf@plt>
  jmp    L102
L111:
  lea    D21(%rip),%rdi
  call   <printf@plt>
  jmp    L314
L8:
  lea    D5(%rip),%rdi
  call   <printf@plt>
  jmp    L86
L433:
  lea    D264(%rip),%rdi
  call   <printf@plt>
  jmp    L513
L453:
  lea    D8(%rip),%rdi
  call   <printf@plt>
  jmp    L360
L254:
  lea    D177(%rip),%rdi
  call   <printf@plt>
  jmp    L180
L168:
  lea    D10(%rip),%rdi
  call   <printf@plt>
  jmp    L438
L259:
  call   <__stack_chk_fail@plt>
```

tool_calls: name: unpack_data
arguments: data_label: D200
data_type: string
name: unpack_data
arguments: data_label: D213
data_type: string
name: unpack_data
arguments: data_label: D15
data_type: string
name: unpack_data
arguments: data_label: D231
data_type: string
name: unpack_data
arguments: data_label: D139
data_type: string
name: unpack_data
arguments: data_label: D222
data_type: string
name: unpack_data
arguments: data_label: D54
data_type: string
name: unpack_data
arguments: data_label: D88
data_type: string
name: unpack_data
arguments: data_label: D154
data_type: string
name: unpack_data
arguments: data_label: D1
data_type: string
name: unpack_data
arguments: data_label: D51
data_type: string
name: unpack_data
arguments: data_label: D269
data_type: string
name: unpack_data
arguments: data_label: D195
data_type: string
name: unpack_data
arguments: data_label: D66
data_type: string
name: unpack_data
arguments: data_label: D226
data_type: string
name: unpack_data
arguments: data_label: D39
data_type: string
name: unpack_data
arguments: data_label: D267
data_type: string
name: unpack_data
arguments: data_label: D141
data_type: string
name: unpack_data
arguments: data_label: D128
data_type: string
name: unpack_data
arguments: data_label: D98
data_type: string
name: unpack_data
arguments: data_label: D157
data_type: string
name: unpack_data
arguments: data_label: D21
data_type: string
name: unpack_data
arguments: data_label: D5
data_type: string
name: unpack_data
arguments: data_label: D264
data_type: string
name: unpack_data
arguments: data_label: D8
data_type: string
name: unpack_data
arguments: data_label: D177
data_type: string
name: unpack_data
arguments: data_label: D10
data_type: string

tool: D200: %s

tool: D213: 
z

tool: D15: 
y

tool: D231: 
x

tool: D139: 
w

tool: D222: 
v

tool: D54: 
u

tool: D88: 
t

tool: D154: 
s

tool: D1: 
r

tool: D51: 
q

tool: D269: 
p

tool: D195: 
o

tool: D66: 
n

tool: D226: 
m

tool: D39: 
l

tool: D267: 
k

tool: D141: 
j

tool: D128: 
i

tool: D98: 
h

tool: D157: 
g

tool: D21: 
f

tool: D5: 
e

tool: D264: 
d

tool: D8: 
c

tool: D177: 
b

tool: D10: 
a

assistant: ```c
int main() {
  char k;
  scanf("%s", &k);
  if (k == 97)
    printf("\nz");
  if (k == 98)
    printf("\ny");
  if (k == 99)
    printf("\nx");
  if (k == 100)
    printf("\nw");
  if (k == 101)
    printf("\nv");
  if (k == 102)
    printf("\nu");
  if (k == 103)
    printf("\nt");
  if (k == 104)
    printf("\ns");
  if (k == 105)
    printf("\nr");
  if (k == 106)
    printf("\nq");
  if (k == 107)
    printf("\np");
  if (k == 108)
    printf("\no");
  if (k == 109)
    printf("\nn");
  if (k == 110)
    printf("\nm");
  if (k == 111)
    printf("\nl");
  if (k == 112)
    printf("\nk");
  if (k == 113)
    printf("\nj");
  if (k == 114)
    printf("\ni");
  if (k == 115)
    printf("\nh");
  if (k == 116)
    printf("\ng");
  if (k == 117)
    printf("\nf");
  if (k == 118)
    printf("\ne");
  if (k == 119)
    printf("\nd");
  if (k == 120)
    printf("\nc");
  if (k == 121)
    printf("\nb");
  if (k == 122)
    printf("\na");
  return 0;
}
```