системы исчисления

#include <iostream>
#include <cmath>

using namespace std;

long long perevod (long long znach, int osn_1)
{
  long long result = 0;
  int shet = 0;
  long long znach_1 = znach;

     while (znach_1 > 0)
     {
       znach_1 = znach_1/10;
       shet++;
     }

    shet--;
    int n = pow(10, shet);

    while (znach > 0)
    {
     result += (znach/n)*(pow(osn_1, shet));
     znach = znach%n;
     shet--;
     n = pow(10, shet);
    }

  return result;
}

long long perevod_1(long long znach, int osn_1, int osn_2)
{
  long long result = 0;
  int shet = 0, n = 0;

  znach = perevod(znach, osn_1);

  while(znach > 0)
  {
    n = pow(10, shet);
    result += (znach % osn_2)*n;
    znach = znach / osn_2;
    shet++;
  }

 return result;
}

int main()
{
  long long znach;
  int osn_1, osn_2;
  cin >> znach >> osn_1 >> osn_2;

   znach = perevod_1(znach, osn_1, osn_2);

  cout << znach;
}