Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
 int64_t N, p, a;
  string ans;
  ans="";
  vector<string> q = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
  if (N>=27**10) {
    for (int i = 0; i <11; i++) {
      a = std::(27,(10-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
   if ((N>=27**9)&&(N<27**10)) {
    for (int i = 0; i <10; i++) {
      a = std::(27,(9-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=27**8)&&(N<27**9)) {
    for (int i = 0; i <9; i++) {
      a = std::(27,(8-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=27**7)&&(N<27**8)) {
    for (int i = 0; i <8; i++) {
      a = std::(27,(7-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=27**6)&&(N<27**7)) {
    for (int i = 0; i <7; i++) {
      a = std::(27,(6-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=27**5)&&(N<27**6)) {
    for (int i = 0; i <6; i++) {
      a = std::(27,(5-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=27**4)&&(N<27**5)) {
    for (int i = 0; i <5; i++) {
      a = std::(27,(4-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
 if ((N>=27**3)&&(N<27**4)) {
    for (int i = 0; i <4; i++) {
      a = std::(27,(3-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=27**2)&&(N<27**3)) {
    for (int i = 0; i <3; i++) {
      a = std::(27,(2-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=27)&&(N<27**2)) {
    for (int i = 0; i <2; i++) {
      a = std::(27,(1-i));
      p=(N-(N%a))/a;
      ans = ans + q.at(p-1);
    }
  }
  if ((N>=1)&&(N<27)) {
    ans = q.at(N-1)
  }
  cout << ans << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:9:13: error: invalid type argument of unary '*' (have 'int')
    9 |   if (N>=27**10) {
      |             ^~~
a.cc:11:16: error: expected unqualified-id before '(' token
   11 |       a = std::(27,(10-i));
      |                ^
a.cc:16:15: error: invalid type argument of unary '*' (have 'int')
   16 |    if ((N>=27**9)&&(N<27**10)) {
      |               ^~
a.cc:16:26: error: invalid type argument of unary '*' (have 'int')
   16 |    if ((N>=27**9)&&(N<27**10)) {
      |                          ^~~
a.cc:18:16: error: expected unqualified-id before '(' token
   18 |       a = std::(27,(9-i));
      |                ^
a.cc:23:14: error: invalid type argument of unary '*' (have 'int')
   23 |   if ((N>=27**8)&&(N<27**9)) {
      |              ^~
a.cc:23:25: error: invalid type argument of unary '*' (have 'int')
   23 |   if ((N>=27**8)&&(N<27**9)) {
      |                         ^~
a.cc:25:16: error: expected unqualified-id before '(' token
   25 |       a = std::(27,(8-i));
      |                ^
a.cc:30:14: error: invalid type argument of unary '*' (have 'int')
   30 |   if ((N>=27**7)&&(N<27**8)) {
      |              ^~
a.cc:30:25: error: invalid type argument of unary '*' (have 'int')
   30 |   if ((N>=27**7)&&(N<27**8)) {
      |                         ^~
a.cc:32:16: error: expected unqualified-id before '(' token
   32 |       a = std::(27,(7-i));
      |                ^
a.cc:37:14: error: invalid type argument of unary '*' (have 'int')
   37 |   if ((N>=27**6)&&(N<27**7)) {
      |              ^~
a.cc:37:25: error: invalid type argument of unary '*' (have 'int')
   37 |   if ((N>=27**6)&&(N<27**7)) {
      |                         ^~
a.cc:39:16: error: expected unqualified-id before '(' token
   39 |       a = std::(27,(6-i));
      |                ^
a.cc:44:14: error: invalid type argument of unary '*' (have 'int')
   44 |   if ((N>=27**5)&&(N<27**6)) {
      |              ^~
a.cc:44:25: error: invalid type argument of unary '*' (have 'int')
   44 |   if ((N>=27**5)&&(N<27**6)) {
      |                         ^~
a.cc:46:16: error: expected unqualified-id before '(' token
   46 |       a = std::(27,(5-i));
      |                ^
a.cc:51:14: error: invalid type argument of unary '*' (have 'int')
   51 |   if ((N>=27**4)&&(N<27**5)) {
      |              ^~
a.cc:51:25: error: invalid type argument of unary '*' (have 'int')
   51 |   if ((N>=27**4)&&(N<27**5)) {
      |                         ^~
a.cc:53:16: error: expected unqualified-id before '(' token
   53 |       a = std::(27,(4-i));
      |                ^
a.cc:58:13: error: invalid type argument of unary '*' (have 'int')
   58 |  if ((N>=27**3)&&(N<27**4)) {
      |             ^~
a.cc:58:24: error: invalid type argument of unary '*' (have 'int')
   58 |  if ((N>=27**3)&&(N<27**4)) {
      |                        ^~
a.cc:60:16: error: expected unqualified-id before '(' token
   60 |       a = std::(27,(3-i));
      |                ^
a.cc:65:14: error: invalid type argument of unary '*' (have 'int')
   65 |   if ((N>=27**2)&&(N<27**3)) {
      |              ^~
a.cc:65:25: error: invalid type argument of unary '*' (have 'int')
   65 |   if ((N>=27**2)&&(N<27**3)) {
      |                         ^~
a.cc:67:16: error: expected unqualified-id before '(' token
   67 |       a = std::(27,(2-i));
      |                ^
a.cc:72:22: error: invalid type argument of unary '*' (have 'int')
   72 |   if ((N>=27)&&(N<27**2)) {
      |                      ^~
a.cc:74:16: error: expected unqualified-id before '(' token
   74 |       a = std::(27,(1-i));
      |                ^
a.cc:80:20: error: expected ';' before '}' token
   80 |     ans = q.at(N-1)
      |                    ^
      |                    ;
   81 |   }
      |   ~