int
fsm_main(const char *s)
{
	const char *p;

	enum {
		S0, S1, S2, S3, S4, S5, S6, S7, S8, S9
	} state;

	state = S0;

	for (p = s; *p != '\0'; p++) {
		switch (state) {
		case S0: /* start */
			switch ((unsigned char) *p) {
			case 'm': state = S1; break;
			default:  return -1; /* leaf */
			}
			break;

		case S1: /* e.g. "m" */
			switch ((unsigned char) *p) {
			case 'i': state = S2; break;
			default:  return -1; /* leaf */
			}
			break;

		case S2: /* e.g. "mi" */
			switch ((unsigned char) *p) {
			case 's': state = S3; break;
			default:  return -1; /* leaf */
			}
			break;

		case S3: /* e.g. "mis" */
			switch ((unsigned char) *p) {
			case 't': state = S4; break;
			case 's': state = S5; break;
			default:  return -1; /* leaf */
			}
			break;

		case S4: /* e.g. "mist" */
			switch ((unsigned char) *p) {
			case 'r': state = S8; break;
			default:  return -1; /* leaf */
			}
			break;

		case S5: /* e.g. "miss" */
			switch ((unsigned char) *p) {
			case 'u': state = S6; break;
			default:  return -1; /* leaf */
			}
			break;

		case S6: /* e.g. "missu" */
			switch ((unsigned char) *p) {
			case 's': state = S7; break;
			default:  return -1; /* leaf */
			}
			break;

		case S7: /* e.g. "missus" */
			return -1; /* leaf */

		case S8: /* e.g. "mistr" */
			switch ((unsigned char) *p) {
			case 'e': state = S9; break;
			default:  return -1; /* leaf */
			}
			break;

		case S9: /* e.g. "mistre" */
			switch ((unsigned char) *p) {
			case 's': state = S6; break;
			default:  return -1; /* leaf */
			}
			break;

		default:
			; /* unreached */
		}
	}

	/* end states */
	switch (state) {
	case S5: return 0x1; /* "(miss|missus|mistress)" */
	case S7: return 0x1; /* "(miss|missus|mistress)" */
	default: return -1; /* unexpected EOT */
	}
}