book_acm

#include <bits/stdc++.h>
using namespace std;

#define INF 0x3f3f3f3f
#define ll long long int
#define MEM(a) memset(a, 0, sizeof(a))
#define MEMM(a) memset(a, -1, sizeof(a))
#define DEB(x, n) \
    cout << (x) << " " << (n) << endl
#define FOR(i, s, e) \
    for(int (i) = (s); (i) < (e); (i)++)
#define CR printf("\n")
#define println(format, ...) ({\
        printf(format "\n", __VA_ARGS__); })
const double PI = acos(-1.0);

int main()
{
#ifdef DEBUG
    // freopen("input", "r", stdin);       //从input文件中读入
    // freopen("output", "w", stdout);     //输出到output文件
#endif

    return 0;
}