#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>


double str_to_num(const char* str1, int base1);
char* num_to_str(double, int base);
int char_to_num(int num, int base);
int num_to_char(int num);

int main(int argc, char *argv[])
{
char* str1;
int base1;
int base2;

if (argc != 4) {
printf("bad input\n");
return -1;
}
else {
str1 = argv[1];
base1 = atoi(argv[2]);
base2 = atoi(argv[3]);
}

double x;

x = str_to_num(str1, base1);
    char* result = num_to_str(x, base2);
        printf("%s\n", result);
free(result);
return 0;
}

void reverse(char* array, int n) {
char temp;
for(int j = 0; j<n/2;j++){
    temp = array[j];
    array[j] = array[n-j-1];
    array[n-j-1] = temp;
}
/*
int j = 0;
while(n/2>0){
    temp = array[j];
    array[j] = array[n-j-1];
    array[n-j-1] = temp;
}
*/
/*
while (n/2 > 0) {
temp = array[0];
array[0] = array[n-1];
array[n-1] = temp;
n--;
}
*/
}

int char_to_num(int num, int base){
int c;
if (isdigit(num)){
c = num - '0';
}
    else{
        num = tolower(num);
        c = num - 'a' + 10;
    }

    if (!(c >= 0 && c < base)) {
    printf("bad input\n");
    exit(1);
    }
return c;
}

int num_to_char(int num){
return (num < 10) ? num + '0' : num + 'A' - 10;
}

double str_to_num(const char* str1, int base1){
double x = 0;
int power_base = -1;

    while (str1[power_base + 1] != 0 && str1[power_base + 1] != '.')
        power_base++;

int j = 0;

for ( ; str1[j] != '\0'; j++) {
    if (str1[j] == '.')
        j++;

int digit = char_to_num(str1[j], base1);
x += digit * pow(base1, power_base);
power_base--;
}
return x;
}

char* num_to_str(double c, int base2){
long long whole = (long long)c;
char* result = (char*)malloc(128);
int i = 0;
double fraction = c - whole;
do {
result[i++] = num_to_char(whole % base2);
whole /= base2;
} while (whole > 0);

//printf("%s\n", result);
int wholeNumOfDigits = i;
reverse(result, i); /*tyt ostanovilsya*/



if (fraction > 0) {
result[i++] = '.';
do {
fraction *= base2;
result[i++/*jopa*/] = num_to_char((int)fraction);
fraction -= (int)fraction;
} while (i-wholeNumOfDigits < 13 && fraction > 0);
}

result[i] = 0;

return result;
}