ABCXYZ

#include <stdio.h>

int a[4] = {1,2,3,4};
int c[10];
int b[4];
int dem = 0;

int Check(int a[]) {
	if (a[0] == 0 || a[3] == 0) return 0;
	return 1;
}

void Tim(int i) {
	int j;
	for (j = 0; j < 4; j++) {
		if (c[a[j]] != 1) {
			b[i] = a[j];
			c[a[j]] = 1;
			if (i == 3) {
				if (Check(b) == 1) {
					dem++;
					for (int g = 0; g < 4; g++) {
						printf("%d",b[g]);
						if (g == 2) printf(".");
					}
					printf("\n");
				}
			} else Tim(i+1);
			c[a[j]] = 0;
		}
	}
}

int main() {
	Tim(0);
	printf("Vay co tat ca %d cach sap!",dem);
}