fn min(a: int, b: int): int {
    return a < b ? a : b;
}

fn max(a: int, b: int): int {
    return a > b ? a : b;
}

fn sign(a: int): int {
    return a > 0 ? 1 : a == 0 ? 0 : -1;
}

fn abs(a: int): int {
    return a * sign(a);
}

fn factorial(n: int): int {
    let res: int = 1;
    for (;n > 0; n = n - 1)
        res = res * n;
    return res;
}


fn strlen(s: char *): int {
    let count: int = 0;
    while (*s != 0) {
        count = count + 1;
        s = s + 1;
    }
    return count;
}

fn strcpy(dst: char *, src: char *) {
    while (*src != 0) {
        *dst = *src;
        dst = dst + 1;
        src = src + 1;
    }
    *dst = '\0';
}

fn strcat(dst: char *, src: char *) {
    while (*dst != 0) {
        dst = dst + 1;
    }
    while (*src != 0) {
        *dst = *src;
        dst = dst + 1;
        src = src + 1;
    }
    *dst = '\0';
}

fn streq(s1: char *, s2: char *): int {
    while (*s1 != 0 && *s2 != 0) {
        if (*s1 != *s2)
            return 0;
        s1 = s1 + 1;
        s2 = s2 + 1;
    }
    return *s1 == *s2;
}

fn putc(c: char) {
    write(0, &c, 1);
}

fn puts(c: char *) {
    let len: int = strlen(c);
    write(1, c, len);
}

fn putsln(c: char *) {
    puts(c);
    putc('\n');
}

fn strrev(s: char *) {
    let len: int = strlen(s);
    let i: int = 0;
    let j: int = len - 1;
    while (i < j) {
        let tmp: char = s[i];
        s[i] = s[j];
        s[j] = tmp;
        i = i + 1;
        j = j - 1;
    }
}