警示后人(If you've WAed on #19 by ST)

inline void prework(){
	for(rint i = 2; i <= max(n, m); ++i)
		Log2[i] = Log2[i>>1]+1;
	for(rint t = 1; t <= 19; ++t)
		for(rint i = 1; i <= n; ++i){
			if(i+(1<<t-1) > n) continue;
			st1a[i][t] = min(st1a[i][t-1], st1a[i+(1<<t-1)][t-1]);
			st1b[i][t] = max(st1b[i][t-1], st1b[i+(1<<t-1)][t-1]);
			st1d[i][t] = min(st1d[i][t-1], st1d[i+(1<<t-1)][t-1]);
			st1e[i][t] = max(st1e[i][t-1], st1e[i+(1<<t-1)][t-1]);
		}
	for(rint t = 1; t <= 19; ++t)
		for(rint i = 1; i <= m; ++i){
			if(i+(1<<t-1) > m) continue;
			st2a[i][t] = min(st2a[i][t-1], st2a[i+(1<<t-1)][t-1]);
			st2b[i][t] = max(st2b[i][t-1], st2b[i+(1<<t-1)][t-1]);
		}
}