user: What would the C source look like for the assembly code provided here:

```asm
<fac>:
  endbr64
  push   %r15
  mov    %edi,%eax
  lea    -0x1(%rdi),%edx
  push   %r14
  sub    $0x2,%eax
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x38,%rsp
  mov    %eax,(%rsp)
  mov    $0x1,%eax
  movl   $0x0,0x4(%rsp)
  cmp    $0x1,%edx
  jbe    L233
L151:
  mov    (%rsp),%eax
  movl   $0x0,0x8(%rsp)
  mov    %eax,%esi
  cmp    $0x1,%eax
  jbe    L14
L231:
  cmp    $0x2,%esi
  je     L145
  lea    -0x2(%rsi),%r8d
  movl   $0x0,0xc(%rsp)
  xor    %esi,%esi
  mov    %r8d,%r9d
  mov    %r9d,%ecx
  cmp    $0x1,%r9d
  je     L214
L101:
  cmp    $0x2,%ecx
  je     L306
  sub    $0x2,%ecx
  xor    %edx,%edx
  xor    %r12d,%r12d
  mov    %ecx,%ebx
  mov    %ebx,%r15d
  cmp    $0x1,%ebx
  je     L81
  nop
L278:
  lea    -0x3(%r15),%r10d
  xor    %r14d,%r14d
  cmp    $0x2,%r15d
  je     L128
L210:
  lea    0x1(%r10),%eax
  mov    %r10d,%ebp
  xor    %r13d,%r13d
  cmp    $0x1,%eax
  jbe    L318
  mov    %r15d,%r11d
  mov    %ebp,%edi
  mov    %ebx,%r15d
  xor    %ebx,%ebx
  cmp    $0x1,%ebp
  je     L160
  nopl   0x0(%rax,%rax,1)
L118:
  mov    %ecx,0x2c(%rsp)
  mov    %r8d,0x28(%rsp)
  mov    %r10d,0x24(%rsp)
  mov    %r11d,0x20(%rsp)
  mov    %r9d,0x1c(%rsp)
  mov    %edx,0x18(%rsp)
  mov    %esi,0x14(%rsp)
  mov    %edi,0x10(%rsp)
  call   <fac>
  mov    0x10(%rsp),%edi
  mov    0x14(%rsp),%esi
  add    %eax,%ebx
  mov    0x18(%rsp),%edx
  mov    0x1c(%rsp),%r9d
  sub    $0x2,%edi
  mov    0x20(%rsp),%r11d
  mov    0x24(%rsp),%r10d
  cmp    $0x1,%edi
  mov    0x28(%rsp),%r8d
  mov    0x2c(%rsp),%ecx
  ja     L118
  add    $0x1,%ebx
  lea    -0x2(%rbp),%eax
  sub    $0x1,%ebp
  add    %ebx,%r13d
  cmp    $0x1,%ebp
  jbe    L234
L280:
  mov    %eax,%ebp
  xor    %ebx,%ebx
  mov    %ebp,%edi
  cmp    $0x1,%ebp
  jne    L118
L160:
  mov    $0x1,%ebx
  lea    -0x2(%rbp),%eax
  sub    $0x1,%ebp
  add    %ebx,%r13d
  cmp    $0x1,%ebp
  ja     L280
L234:
  add    $0x1,%r13d
  mov    %r15d,%ebx
  lea    -0x2(%r10),%eax
  mov    %r11d,%r15d
  add    %r13d,%r14d
  cmp    $0x1,%r10d
  ja     L142
L39:
  add    $0x1,%r14d
  sub    $0x2,%r15d
  add    %r14d,%r12d
  cmp    $0x1,%r15d
  ja     L278
L292:
  add    $0x1,%r12d
  lea    -0x2(%rbx),%eax
  sub    $0x1,%ebx
  add    %r12d,%edx
  cmp    $0x1,%ebx
  jbe    L95
L6:
  mov    %eax,%ebx
  xor    %r12d,%r12d
  mov    %ebx,%r15d
  cmp    $0x1,%ebx
  jne    L278
L81:
  mov    $0x1,%r12d
  lea    -0x2(%rbx),%eax
  sub    $0x1,%ebx
  add    %r12d,%edx
  cmp    $0x1,%ebx
  ja     L6
L95:
  add    $0x1,%edx
L139:
  add    %edx,%esi
  cmp    $0x1,%ecx
  ja     L101
  add    $0x1,%esi
L272:
  lea    -0x2(%r9),%eax
  sub    $0x1,%r9d
  add    %esi,0xc(%rsp)
  cmp    $0x1,%r9d
  jbe    L70
  mov    %eax,%r9d
  xor    %esi,%esi
  mov    %r9d,%ecx
  cmp    $0x1,%r9d
  jne    L101
L214:
  mov    $0x1,%esi
  jmp    L272
L128:
  mov    $0x1,%r14d
  sub    $0x2,%r15d
  add    %r14d,%r12d
  cmp    $0x1,%r15d
  ja     L278
  jmp    L292
  nopl   (%rax)
L318:
  mov    $0x1,%r13d
  lea    -0x2(%r10),%eax
  add    %r13d,%r14d
  cmp    $0x1,%r10d
  jbe    L39
L142:
  mov    %eax,%r10d
  jmp    L210
L306:
  mov    $0x1,%edx
  xor    %ecx,%ecx
  jmp    L139
L70:
  mov    0xc(%rsp),%eax
  add    $0x1,%eax
L90:
  add    %eax,0x8(%rsp)
  mov    %r8d,%esi
  cmp    $0x1,%r8d
  ja     L231
  mov    0x8(%rsp),%eax
  add    $0x1,%eax
  jmp    L294
L14:
  mov    $0x1,%eax
L294:
  add    %eax,0x4(%rsp)
  mov    (%rsp),%eax
  lea    -0x2(%rax),%edx
  sub    $0x1,%eax
  cmp    $0x1,%eax
  jbe    L216
  mov    %edx,(%rsp)
  jmp    L151
L216:
  mov    0x4(%rsp),%eax
  add    $0x1,%eax
L233:
  add    $0x38,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L145:
  mov    $0x1,%eax
  xor    %r8d,%r8d
  jmp    L90
```

assistant: ```c
int fac(int n) {
  if (n == 1 || n == 2)
    return 1;
  return fac(n - 1) + fac(n - 2);
}
```