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

#define LINES 1000

int compare(const void *a, const void *b);

int main()
{
	// populate arrays from file
	FILE *input;
	input = fopen("./input", "r");
	unsigned int left[LINES];
	unsigned int right[LINES];

	for (int i = 0; i < LINES; i++) {
		fscanf(input, "%d", &left[i]);
		// printf("%d left: %d	", i, left[i]);
		fscanf(input, "%d", &right[i]);
		// printf("%d right: %d\n", i, right[i]);
	}

	// sort arrays
	qsort(left, LINES, sizeof(int), compare);
	qsort(right, LINES, sizeof(int), compare);
	/*
	for (int i = 0; i < LINES; i++) {
		printf("%d left: %d	", i, left[i]);
		printf("%d right: %d\n", i, right[i]);
	}
	*/

	// compare each element n, add its difference to sum-var
	unsigned long int distance = 0;
	for (int i = 0; i < LINES; i++) {
		distance += abs(left[i] - right[i]);
	}
	printf("distance: %d\n", distance);
}

int compare(const void *a, const void *b)
{
	int int_a = * ((int*) a);
	int int_b = * ((int*) b);
	
	if (int_a == int_b) return 0;
	else if (int_a < int_b) return -1;
	else return 1;
}