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

	enum {
		S0, S1, S2, S3, S4, S5, S6, S7, S8, S9, 
		S10
	} state;

	state = S0;

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

		case S1: /* e.g. "s" */
			switch ((unsigned char) *p) {
			case 't': state = S2; break;
			default:  return -1; /* leaf */
			}
			break;

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

		case S3: /* e.g. "ste" */
			switch ((unsigned char) *p) {
			case 'p': state = S4; break;
			case 'v': state = S5; break;
			default:  return -1; /* leaf */
			}
			break;

		case S4: /* e.g. "step" */
			switch ((unsigned char) *p) {
			case 'h': state = S9; break;
			default:  return -1; /* leaf */
			}
			break;

		case S5: /* e.g. "stev" */
			switch ((unsigned char) *p) {
			case 'e': state = S6; break;
			case 'i': state = S7; break;
			default:  return -1; /* leaf */
			}
			break;

		case S6: /* e.g. "steve" */
			switch ((unsigned char) *p) {
			case 'n': state = S8; break;
			default:  return -1; /* leaf */
			}
			break;

		case S7: /* e.g. "stevi" */
			switch ((unsigned char) *p) {
			case 'e': state = S8; break;
			default:  return -1; /* leaf */
			}
			break;

		case S8: /* e.g. "stevie" */
			return -1; /* leaf */

		case S9: /* e.g. "steph" */
			switch ((unsigned char) *p) {
			case 'e': state = S10; break;
			default:  return -1; /* leaf */
			}
			break;

		case S10: /* e.g. "stephe" */
			switch ((unsigned char) *p) {
			case 'n': state = S8; break;
			default:  return -1; /* leaf */
			}
			break;

		default:
			; /* unreached */
		}
	}

	/* end states */
	switch (state) {
	case S6: return 0x1; /* "(s|S)t(even|ephen|eve|evie)" */
	case S8: return 0x1; /* "(s|S)t(even|ephen|eve|evie)" */
	default: return -1; /* unexpected EOT */
	}
}