#include<stdio.h>



int is_prime(int number) {
	for (int i = 2; i <= number / 2; i++) {
		if (number %i == 0) {
			return 0;
		}
	}
	return 1;
}
int next_prime(int number) {
	for (int i = 1;; i++) {
		if (is_prime(number + i)) {
			return number + i;
		}
	}
	return 0;
}

int main() {
	for (int i = 0; i < 10000; i++) {

		if (is_prime(i)) {
			int np = next_prime(i);
			if (np - i == 2) {
				printf("%d - %d\n", i, np);
			}


		}
	}

	getchar();
}