struct FastIO {
static const int S = ;
int wpos;
char wbuf[S];
FastIO() : wpos() { }
inline int xchar() {
static char buf[S];
static int len = , pos = ;
if (pos == len) pos = , len = fread(buf, , S, stdin);
if (pos == len) return -;
return buf[pos++];
}
inline int xint() {
int c = xchar(), x = , s = ;
while (c <= ) c = xchar();
if (c == '-') s = -, c = xchar();
for (; '' <= c && c <= ''; c = xchar()) x = x * + c - '';
return x * s;
}
~FastIO() {
if (wpos) fwrite(wbuf, , wpos, stdout), wpos = ;
}
} io;