import std.stdio;
import std.conv;
import std.string;
import std.math;
import std.algorithm;

void main(){
	auto nk = readln.split.map!(to!int);
	int[] numMemo; numMemo.length = 1_000_005;
	int wi;
	int wiCount(int j){ return numMemo[j..$].reduce!("a + b"); }
	foreach(i; 1..nk[0]+1){
		wi = readln.chomp.to!int;
		if(wi > 0){
			if(wiCount(wi) < nk[1] ){ numMemo[wi] += 1; }
		}
		else{ numMemo[abs(wi)] = max(0, numMemo[abs(wi)] - 1); }
	}
	auto res = numMemo.reduce!("a + b");
	res.writeln;
}