int parseMonth(const char *input) {
    int rv=-1;
    const char *p=input;
    int len=strlen(input);

    /* Short cut when the length falls outside of
        expected ranges */
    if(len < 3 || len > 3) {
        return rv;
    }

    /* Collapsing anything with fewer than 4 paths */
    /* 12 matches for "" */
    switch(p[0]) {
        case 'A':
            /* 2 match(es) for "A" */
            if(memcmp(p, "Apr\0", 4) == 0) {
                rv=3;
            } else if(memcmp(p, "Aug\0", 4) == 0) {
                rv=7;
            }
        break;
        case 'D':
            /* 1 match(es) for "D" */
            if(memcmp(p, "Dec\0", 4) == 0) {
                rv=11;
            }
        break;
        case 'F':
            /* 1 match(es) for "F" */
            if(memcmp(p, "Feb\0", 4) == 0) {
                rv=1;
            }
        break;
        case 'J':
            /* 3 match(es) for "J" */
            if(memcmp(p, "Jan\0", 4) == 0) {
                rv=0;
            } else if(memcmp(p, "Jun\0", 4) == 0) {
                rv=5;
            } else if(memcmp(p, "Jul\0", 4) == 0) {
                rv=6;
            }
        break;
        case 'M':
            /* 2 match(es) for "M" */
            if(memcmp(p, "Mar\0", 4) == 0) {
                rv=2;
            } else if(memcmp(p, "May\0", 4) == 0) {
                rv=4;
            }
        break;
        case 'O':
            /* 1 match(es) for "O" */
            if(memcmp(p, "Oct\0", 4) == 0) {
                rv=9;
            }
        break;
        case 'N':
            /* 1 match(es) for "N" */
            if(memcmp(p, "Nov\0", 4) == 0) {
                rv=10;
            }
        break;
        case 'S':
            /* 1 match(es) for "S" */
            if(memcmp(p, "Sep\0", 4) == 0) {
                rv=8;
            }
        break;
    }
    return rv;
}