#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <cctype>
#include <cassert>
#include <climits>
#include <string>
#include <bitset>
#include <cfloat>
#include <unordered_set>
#include <unordered_map>
#include <iomanip>
//#pragma GCC optimize("Ofast")
//#define _GLIBCXX_DEBUG
using namespace std;
typedef long double ld;
typedef long long int ll;
typedef unsigned long long int ull;
//#define int ll
typedef vector<int> vi;
typedef vector<char> vc;
typedef vector<bool> vb;
typedef vector<double> vd;
typedef vector<string> vs;
typedef vector<ll> vll;
typedef pair<int,int> pii;
typedef vector<pair<int,int> > vpii;
typedef vector<vector<int> > vvi;
typedef vector<vector<char> > vvc;
typedef vector<vector<string> > vvs;
typedef vector<vector<ll> > vvll;
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define rrep(i,n) for(int i = 1; i <= (n); ++i)
#define irep(it, stl) for(auto it = stl.begin(); it != stl.end(); it++)
#define drep(i,n) for(int i = (n) - 1; i >= 0; --i)
#define fin(ans) cout << (ans) << '\n'
#define mp(p,q) make_pair(p, q)
#define pb(n) push_back(n)
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define floatprec(dig) fixed << setprecision(dig)
#define Sort(a) sort(a.begin(), a.end())
#define Rort(a) sort(a.rbegin(), a.rend())
#define MATHPI acos(-1)
#define itn int;
#define invar(typ, var) typ var; cin >> var;
int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
template <class T> inline bool chmax(T& a,T b){if(a<b){a=b;return 1;} return 0;}
template <class T> inline bool chmin(T& a,T b){if(a>b){a=b;return 1;} return 0;}
struct io{io(){ios::sync_with_stdio(false);cin.tie(0);}};
const int INF = INT_MAX / 2;
const ll LLINF = 1LL<<60;
constexpr ll MOD = 1000000007;
const double EPS = 1e-9;

signed main(void) {
  cin.tie(0); ios::sync_with_stdio(false);
  
  int N, K, C;
  cin >> N >> K >> C;
  
  string S;
  cin >> S;
  
  //貪欲
  vi gr;
  int i = 0;
  while(true) {
    if(S[i] == 'o') {
      gr.push_back(i);
      i += C + 1;
    } else {
      i++;
    }
    
    if(i >= S.size()) {
      break;
    }
  }
  
  if(gr.size() > K) {
    //選択の余地があるので，共通で働く日は無い
    return 0;
  }
  
  //他は常に選ぶことが可能
  
  //後ろ向き
  vi lz;
  i = S.size()-1;
  while(true) {
    if(S[i] == 'o') {
      lz.push_back(i);
      i -= C + 1;
    } else {
      i--;
    }
    
    if(i < 0) {
      break;
    }
  }
  
  sort(all(lz));
  
  // //遅延
  // //直近のoのINDEX
  // vi lasto(N);
  // //それ以前の最大回数
  // vi dp(N);
  // lasto[0] = S[0] == 'o' ? 0 : -1;
  // dp[0]    = 0;
  // vi lz;
  
  // for(int i=1; i<S.size(); i++) {
  //   lasto[i] = S[i] == 'o' ? i : lasto[i-1];
    
  //   dp[i] = dp[i - 1];
  //   if(i-C-1>=0 && S[i] == 'o' && lasto[i-C-1] != -1) {
  //     int newi = dp[i-C-1] + 1;
  //     if(dp[i] < newi) {
  //       lz.push_back(lasto[i-C-1]);
  //       dp[i] = newi;
  //     }
  //   }
  // }
  
  // dp[N-1] + 1
  
  for(int i=0; i<lz.size(); i++) {
    if(lz[i] == gr[i]) {
      fin(lz[i]+1);
    }
  }
  
}
//16 4 3
/*
1234567890123456
ooxxoxoxxxoxoxxo

5 2 3
12345
ooxoo
00001
*/
//
/*
11 3 2
12345678901
ooxxxoxxxoo
00000111122
12222666601
<- up時のo = 最後のoより後．= 最後のoを記録できる
v.s. 貪欲


*/

Measured memory_bytes: 3468