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

int main() {
	long long N, K, L; cin >> N >> K >> L;
	string S; cin >> S;

	long long now = 0;
	bool flag = false;
	for (int i = 0; i < N; i++) {
		if (S[i] == '0') {
			now++;
			if (now >= K) flag = true;
		}
		else now = 0;
	}
	for (int i = 0; i < N; i++) {
		if (S[i] == '0') {
			now++;
			if (now >= K) flag = true;
		}
		else now = 0;
	}
	now = 0;
	for (int i = 0; i < N; i++) {
		if (S[i] == '1') {
			now++;
			if (now >= K) flag = true;
		}
		else now = 0;
	}
	for (int i = 0; i < N; i++) {
		if (S[i] == '1') {
			now++;
			if (now >= K) flag = true;
		}
		else now = 0;
	}

	if (!flag) cout << N * L << endl;
	else {
		long long sum = 0;
		for (int i = 0; i < N; i++) {
			if (S[i] == '0') sum += 1;
			else sum += 2 * K - 2;
		}
		sum *= L;

		long long amari = sum % (2 * K - 1);
		if (amari == 0) cout << 2 * (K - 1) << endl;
		else if (amari < K) cout << 2 * K - 2 - amari << endl;
		else cout << amari - 1 << endl;
	}
}