快读 适用于整数，不适合字符以及字符串 当输入中有大量空格时，最好不要用快读！！
inline int read() {
int i = 0, j = 1;
char ch = getchar();
while (ch<'0' || ch>'9') { if (ch == '-')j = -1; ch = getchar(); }
while (ch >= '0'&&ch <= '9') i = i * 10 + ch - '0', ch = getchar();
return i*j;
}