缺省源

#include <bits/stdc++.h>
#define max Max
#define min Min
#define Max(a, b) (((a) > (b)) ? (a) : (b))
#define Min(a, b) (((a) < (b)) ? (a) : (b))
#define y1 abcdedfghijklmnopqrstuvwxyz
#define swap my_swap
template <typename T> void my_swap(T &x, T &y) {return x ^= y ^= x ^= y, void();}
namespace FASTIO {
    void read() {return;} void write() {return;}
    template <typename T, typename ...T2> void read(T &x, T2 &...oth) {char ch = getchar(), f = 1; while (ch > '9' || ch < '0') {if (ch == '-') {f = ~f + 1;} ch = getchar()} while (ch >= '0' && ch <= '9') {x = (x << 3) + (x << 1) + (ch ^ '0'); ch = getchar();} x *= f; read(oth...);}
    template <typename T, typename ...T2> void write(T x, T2 ...oth) {if (x < 0) {putchar('-');x = -x;} while (x) {putchar(x % 10 + '0'); x /= 10;} write(oth...);}
}
#define read FASTIO::read
#define write FASTIO::write