OK

#include <stdio.h>
// d-2
const char *pwd[] = { "", "", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz" };
const int dlen[] = {0, 0, 3, 3, 3, 3, 3, 4, 3, 4};
int cnt[10], t;
int st[10], fcnt[10];

int main() {

int n;
scanf("%d", &n);
t = 1;
for (int i=1; i<=n; i++) {
	scanf("%d", &st[i]);
	t *= dlen[st[i]];
}
printf("%d\n", t);

while (1) {
	for (int i=1; i<=n; i++) {
		putchar(pwd[st[i]][fcnt[i]]);
	}
	putchar('\n');
	
	for (int i=n; i>=1; i--) {
		fcnt[i]++;
		if (i==1 && fcnt[i]==dlen[st[i]]) goto END; 
		if (fcnt[i] == dlen[st[i]]) fcnt[i] = 0;
		else break;
	} 
}
END:


return 0;

}