#include <stdio.h>
#include <stdlib.h>
	
int main(void) 
{
	int n, i;
	scanf("%d", &n);

	int *v = malloc(n * sizeof(int));
	for (i = 0; i < n; i++) {
		scanf("%d", &v[i]);
	}
	int first = v[0], second = v[1];
	
	for (i = 1; i < n; i++) {
		if (second - first > 1) {
			printf("%d-%d\n", first + 1, second - 1);
		}
		first = second;
		second = v[i + 1];
	}
	printf("%d-%d\n", v[n - 1] + 1, 100);
	free(v);
	return 0;
}