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

int main()
{

    FILE *file = fopen("input.txt", "r");
    int length;
    char *buffer;
    int *numericArray;

    if (file) {

        fseek(file, 0, SEEK_END);
        length = ftell(file);

        buffer = malloc(length);
        if (buffer == NULL) {
            return EXIT_FAILURE;
        }

        fseek(file, 0, SEEK_SET);
        fread(buffer, 1, length, file);

        fclose(file);

        char *bufferCopy;
        strcpy(bufferCopy, buffer);

        char *nextNumber = strtok(bufferCopy, ",");

        int arrayLength = 0;
        while (nextNumber != NULL) {
            nextNumber = strtok(NULL, ",");
            arrayLength++;
        }

        numericArray = malloc(sizeof(int) * arrayLength);
        if (numericArray == NULL) {
            return EXIT_FAILURE;
        }

        int i = 0;
        nextNumber = strtok(buffer, ",");
        while (nextNumber != NULL) {
            numericArray[i] = atoi(nextNumber);
            nextNumber = strtok(NULL, ",");
            i++;
        }

        for (i = 0; i < arrayLength; i++) {
            int j;
            for (j = i + 1; j < arrayLength; j++) {
                if (compare(numericArray[i], numericArray[j])) {
                    int k;
                    for (k = j; k < arrayLength - 1; k++) {
                        numericArray[k] = numericArray[k+1];
                    }
                    arrayLength--;
                    numericArray = realloc(numericArray, sizeof(int) * arrayLength);
                    if (numericArray == NULL) {
                        return EXIT_FAILURE;
                    }
                }
            }
        }

        file = fopen("output.txt", "w");
        for (i = 0; i < arrayLength; i++) {
            fprintf(file, "%d", numericArray[i]);
            if (i < arrayLength - 1) {
                fprintf(file, ",", numericArray[i]);
            }
        }
        fclose(file);

    }

    return EXIT_SUCCESS;

}

int compare(int a, int b) {

    if (a == b) {
        return 1;
    }
    else {
        return 0;
    }

}