定数
const int N = 1000;
const int inf = (int)1e9 + 1;
const ll big = (ll)1e18 + 1;
const int P = 31;
const int MOD = (int)1e9 + 7;
const int MOD1 = (int)1e9 + 9;
const int MAX_INT = (1 << 31) - 1;
const double eps = 1e-6;
const double pi = atan2(0, -1);
const double pi2 = atan(1) * 4;