user: Please show me the C implementation that matches the assembly code listed below:

```asm
<main>:
  endbr64
  push   %r13
  mov    $0x37,%edi
  xor    %r13d,%r13d
  push   %r12
  mov    $0x37,%r12d
  push   %rbp
  lea    D19(%rip),%rbp
  push   %rbx
  sub    $0x8,%rsp
  jmp    L17
  nopl   (%rax)
L1:
  movsbl 0x0(%rbp),%edi
L17:
  call   <char_to_int@plt>
  movsbl 0x1(%rbp),%edi
  mov    %eax,%ebx
  call   <char_to_int@plt>
  movsbl 0x2(%rbp),%edi
  imul   %eax,%ebx
  call   <char_to_int@plt>
  movsbl 0x3(%rbp),%edi
  imul   %eax,%ebx
  call   <char_to_int@plt>
  movsbl %r12b,%edi
  imul   %eax,%ebx
  call   <char_to_int@plt>
  imul   %ebx,%eax
  cmp    %eax,%r13d
  cmovl  %eax,%r13d
  movzbl 0x5(%rbp),%r12d
  add    $0x1,%rbp
  test   %r12b,%r12b
  jne    L1
  mov    %r13d,%esi
  lea    D3(%rip),%rdi
  call   <printf@plt>
  add    $0x8,%rsp
  xor    %eax,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  ret
```

tool_calls: name: unpack_data
arguments: data_label: D19
datatype: string
name: unpack_data
arguments: data_label: D3
datatype: string

tool: D19: 7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450

tool: D3: PRODUCT: %d


assistant: ```c
int main() {
  char *longnumber = "73167176531330624919225119674426574742355349194934"
                     "96983520312774506326239578318016984801869478851843"
                     "85861560789112949495459501737958331952853208805511"
                     "12540698747158523863050715693290963295227443043557"
                     "66896648950445244523161731856403098711121722383113"
                     "62229893423380308135336276614282806444486645238749"
                     "30358907296290491560440772390713810515859307960866"
                     "70172427121883998797908792274921901699720888093776"
                     "65727333001053367881220235421809751254540594752243"
                     "52584907711670556013604839586446706324415722155397"
                     "53697817977846174064955149290862569321978468622482"
                     "83972241375657056057490261407972968652414535100474"
                     "82166370484403199890008895243450658541227588666881"
                     "16427171479924442928230863465674813919123162824586"
                     "17866458359124566529476545682848912883142607690042"
                     "24219022671055626321111109370544217506941658960408"
                     "07198403850962455444362981230987879927244284909188"
                     "84580156166097919133875499200524063689912560717606"
                     "05886116467109405077541002256983155200055935729725"
                     "71636269561882670428252483600823257530420752963450";
  int product = 0;
  char *c1, *c2, *c3, *c4, *c5;
  int tempproduct;
  c1 = longnumber;
  c2 = longnumber + 1;
  c3 = longnumber + 2;
  c4 = longnumber + 3;
  c5 = longnumber + 4;
  while (*c5 != '\0') {
    tempproduct = 1;
    tempproduct *= char_to_int(*c1);
    tempproduct *= char_to_int(*c2);
    tempproduct *= char_to_int(*c3);
    tempproduct *= char_to_int(*c4);
    tempproduct *= char_to_int(*c5);
    if (tempproduct > product)
      product = tempproduct;
    c1++;
    c2++;
    c3++;
    c4++;
    c5++;
  }
  printf("PRODUCT: %d\n", product);
  return 0;
}
```