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#include <bits/stdc++.h>
using namespace std;
#define fwd(i, a, n) for (int i = (a); i < (n); i++)
#define rep(i, n) fwd(i, 0, n)
#define all(X) X.begin(), X.end()
#define sz(X) int(size(X))
#define pb push_back
#define eb emplace_back
#define st first
#define nd second
using pii = pair<int, int>; using vi = vector<int>;
using ll = long long; using ld = long double;
#ifdef LOC
auto SS = signal(6, [](int) { *(int *)0 = 0; });
#define DTP(x, y) auto operator << (auto &o, auto a) -> decltype(y, o) { o << "("; x; return o << ")"; }
DTP(o << a.st << ", " << a.nd, a.nd);
DTP(for (auto i : a) o << i << ", ", all(a));
void dump(auto... x) { (( cerr << x << ", " ), ...) << '\n'; }
#define deb(x...) cerr << setw(4) << __LINE__ << ":[" #x "]: ", dump(x)
#else
#define deb(...) 0
#endif

#define S 8192

int T[S];
int pref[S];

int officeT[S];
int officePref[S];

int tree[2*S+7];

void add(int w, int c) {
	w = w+S-1;
	while(w != 0) {
		tree[w] = min(tree[w], c);
		w /= 2;
	}
}

int findFirst(int x) {
	if(tree[1] > x)
		return -1;
	
	int w = 1;
	while(w < S) {
		if(tree[w*2] <= x)
			w = w * 2;
		else 
			w = w * 2 + 1;
	}
	return w-S+1;
}

int32_t main() {
	cin.tie(0)->sync_with_stdio(0);
	cout << fixed << setprecision(10);
	int n,k,t;
	cin >> n >> k >> t;
	string s;
	cin >> s;

	int office = 0;
	for(int i = 0; i < n; i++) {
		char c = s[i];
		if(c == '1') {
			office++;
			officeT[i+1] = 1;
		}
		if(c != '3') {
			T[i+1] = 1;
		}
	}

	for(int i = 1; i <= n; i++){
		pref[i] = pref[i-1] + T[i];
		officePref[i] = officePref[i-1] + officeT[i];
	}

	if(pref[n] <= k) {
		cout << n << "\n";
		return 0;
	}
	if(office <= k) {
		cout << n-(pref[n]-k) << "\n";
		return 0;
	}


	for(int i = 1; i < 2*S; i++){
		tree[i] = 1e9;
	}

	int ans = -1;
	for(int i = n-2*t+1; i >= 1; i--) {
		//we start going at time i
		
		//we don't come back
		// {
		// 	int usedOnDrive = pref[i+t-1] - pref[i-1];
		// 	if(usedOnDrive + officePref[i-1] <= k) {
		// 		int meetingsOutside = pref[i-1];
		// 		int skippedMeetings = min(meetingsOutside, k-usedOnDrive);
		// 		int attend = meetingsOutside - skippedMeetings;
		// 		ans = max(ans, (i-1) - attend);
		// 		deb(i,k,usedOnDrive,(i-1) - attend);
		// 	}
		// }
		// if(i + 2 * t - 1 <= n) {

		//add return at i+t
		//cost of return is number of meeting during drive and office meetings later
		int driveS = i+t;
		int driveT = driveS + t - 1;

		add(i+t, (pref[driveT] - pref[driveS - 1]) + officePref[n] - officePref[driveT]);
		// deb(i+t,(pref[driveT] - pref[driveS - 1]) + officePref[n] - officePref[driveT]);
		driveS = i;
		driveT = driveS+t-1;

		//how many we can still skip
		int lim = k - ((pref[driveT] - pref[driveS-1]) + officePref[driveS-1]);
		
		int p = findFirst(lim);
		deb(i,lim,p);
		if(p != -1) {
			
			driveS = i;
			driveT = driveS+t-1;
			int usedOnDrive = (pref[driveT] - pref[driveS-1]);

			driveS = p;
			driveT = driveS+t-1;
			usedOnDrive += (pref[driveT] - pref[driveS-1]);
			
			int outsideOffice = i-1;
			outsideOffice += (n-driveT);

			int meetingsOutside = pref[i-1] + (pref[n] - pref[driveT]);
			int skippedMeetings = min(meetingsOutside, k-usedOnDrive);
			int attend = meetingsOutside - skippedMeetings;
			ans = max(ans, outsideOffice - attend);
			deb(i,k,p,outsideOffice,usedOnDrive,meetingsOutside,skippedMeetings,attend,outsideOffice - attend);
		}

		// }
	}
	cout << ans << "\n";
}