typedef unsigned long size_t;

void *memset(void *s, int c, size_t n) {
     for(size_t i = 0; i<n; i++) ((char *)s)[i] = (char)c;
     return s;
}

void *memcpy(void *restrict dest,
             const void *restrict src, size_t n) {
     for(size_t i =0; i<n; i++) ((char *)dest)[i]=((char *)src)[i];
     return dest;
}


//@ ensures a <= \result <= b;
int interval(int a, int b);