typedef unsigned long size_t;
void *memset(void *s, int c, size_t n) {
    unsigned char *p = (unsigned char *)s;
    while (n--) *p++ = (unsigned char)c;
    return s;
}
void *memcpy(void *d, const void *s, size_t n) {
    unsigned char *a = (unsigned char *)d;
    const unsigned char *b = (const unsigned char *)s;
    while (n--) *a++ = *b++;
    return d;
}
void exit(int code) {
    register long a0 __asm__("a0") = code;
    register long a7 __asm__("a7") = 93;
    __asm__ volatile("ecall" :: "r"(a0), "r"(a7));
    for (;;) {}
}