#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <gmp.h>

int main(int argc, char *argv[])
{
      int debug=0;

      switch(argc)
      {
            case 1:break;
            case 2:
                  if(strcmp(argv[1],"-v")==0 || strcmp(argv[1],"--verbose")==0)
                        debug=1;
                  break;
            default:return 1;
      }

      int a=2,b;
      mpz_t digit,maximum,power,sum_digits;
      mpz_init(digit);
      mpz_init_set_si(maximum,0);
      mpz_init(power);
      mpz_init(sum_digits);

      for(;a<100;a++)
            for(b=2;b<100;b++)
            {
                  mpz_set_si(sum_digits,0);
                  mpz_ui_pow_ui(power,a,b);
                  do
                  {
                        mpz_tdiv_qr_ui(power,digit,power,10);
                        mpz_add(sum_digits,sum_digits,digit);
                  }while(mpz_cmp_si(power,0)>0);
                  if(mpz_cmp(sum_digits,maximum)>0)
                  {
                        mpz_set(maximum,sum_digits);
                        if(debug==1)
                        {
                              gmp_printf("%Zd is the new maximum sum ",maximum);
                              gmp_printf("of digits reached with %i^%i \n",a,b);
                        }
                  }
            }
      gmp_printf("\n\t%Zd\n\n",maximum);
      return 0;
}