//#include <bits/stdc++.h>
#include <iostream>
#include <iomanip>
#include <cmath>
#include <algorithm>
#include <climits>
#include <functional>
#include <cstring>
#include <string>
#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <bitset>
#include <complex>
#include <random>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/priority_queue.hpp>
#define itn int
#define nit int
#define ll long long
#define ms multiset
#define F(i,a,b) for(register int i=a,i##end=b;i<=i##end;++i)
#define UF(i,a,b) for(register int i=a,i##end=b;i>=i##end;--i)
#define re register
#define ri re int
#define il inline
#define pii pair<int,int>
#define cp complex<double>
#define vi vector<int>
#define ull unsigned long long
#define mem0(x) memset(x,0,sizeof(x))
#define mem0x3f(x) memset(x,0x3f,sizeof(x))
using namespace std;
//using namespace __gnu_pbds;
const double Pi=acos(-1);
namespace fastIO {
	template<class T>
	inline void read(T &x) {
		x=0;
		bool fu=0;
		char ch=0;
		while(ch>'9'||ch<'0') {
			ch=getchar();
			if(ch=='-')fu=1;
		}
		while(ch<='9'&&ch>='0') x=(x*10-48+ch),ch=getchar();
		if(fu)x=-x;
	}
	inline int read() {
		int x=0;
		bool fu=0;
		char ch=0;
		while(ch>'9'||ch<'0') {
			ch=getchar();
			if(ch=='-')fu=1;
		}
		while(ch<='9'&&ch>='0') x=(x*10-48+ch),ch=getchar();
		return fu?-x:x;
	}
	template<class T,class... Args>
	inline void read(T& t,Args&... args) {
		read(t);
		read(args...);
	}
	char _n_u_m_[40];
	template<class T>
	inline void write(T x) {
		if(x==0){
			putchar('0');
			return;
		}
		T tmp = x > 0 ? x : -x ;
		if( x < 0 ) putchar('-') ;
		register int cnt = 0 ;
		while( tmp > 0 ) {
			_n_u_m_[ cnt ++ ] = tmp % 10 + '0' ;
			tmp /= 10 ;
		}
		while( cnt > 0 ) putchar(_n_u_m_[ -- cnt ]) ;
	}
	template<class T>
	inline void write(T x ,char ch) {
		write(x);
		putchar(ch);
	}
}
using namespace fastIO;
int n,a,b,prea[200002],preb[200002],len,dp[200002],t1[200002],t2[200002];
char c[200002];
int mmax[70000002],lc[70000002],rc[70000002],cnt,LC[5000002],RC[5000002],tot,id[5000002],t[200002];
#define mid ((l+r)>>1)
inline void add(int pos,int l,int r,int q,int v){
	mmax[pos]=max(mmax[pos],v);
	if(l==r)return;
	if(q<=mid){
		if(!lc[pos])lc[pos]=++cnt;
		add(lc[pos],l,mid,q,v);
	}else{
		if(!rc[pos])rc[pos]=++cnt;
		add(rc[pos],mid+1,r,q,v);
	}
}
inline void Add(int pos,int l,int r,int x,int y,int v){//if(x==5)cerr<<pos<<" "<<l<<" "<<r<<"K"<<endl;
	add(id[pos],0,n,y,v);
	if(l==r)return;
	if(x<=mid){
		if(!LC[pos]){
			LC[pos]=++tot;
			id[LC[pos]]=++cnt;
		}
		Add(LC[pos],l,mid,x,y,v);
	}else{
		if(!RC[pos]){
			RC[pos]=++tot;
			id[RC[pos]]=++cnt;
		}
		Add(RC[pos],mid+1,r,x,y,v);
	}
}
inline int query(int pos,int l,int r,int q){
	if(!pos||q>=r)return mmax[pos];
	if(q<=mid)return query(lc[pos],l,mid,q);
	return max(mmax[lc[pos]],query(rc[pos],mid+1,r,q));
}
inline int Query(int pos,int l,int r,int x,int y){//cerr<<pos<<" "<<l<<" "<<r<<" "<<id[pos]<<endl;
	if(!pos||x>=r)return query(id[pos],0,n,y);
	if(x<=mid)return Query(LC[pos],l,mid,x,y);
	return max(query(id[LC[pos]],0,n,y),Query(RC[pos],mid+1,r,x,y));
}
namespace sub{
	void solve(){
		F(i,1,n){
		dp[i]=dp[i-1];
		F(j,1,i/len)if(prea[i]-prea[i-len*j]<=a*j&&preb[i]-preb[i-len*j]<=b*j)dp[i]=max(dp[i],dp[i-len*j]+j);
	}
	cout<<dp[n];
	}
}
int main() {
//	freopen("data.txt","r",stdin);
	cin>>n>>a>>b;len=a+b;
	scanf("%s",c+1);
	F(i,1,n){
		if(c[i]=='W')c[i]='?';
		else if(c[i]=='R')c[i]='0';
		else c[i]='1';
		if(c[i]=='0')prea[i]=prea[i-1]+1,preb[i]=preb[i-1];
		else if(c[i]=='1')prea[i]=prea[i-1],preb[i]=preb[i-1]+1;
		else prea[i]=prea[i-1],preb[i]=preb[i-1];
	}
	if(n<=1000||len>=1000){
	//	sub::solve();
	//	return 0;
	}
	F(i,1,n){
		prea[i]-=i/len*a;
		preb[i]-=i/len*b;
		t1[i]=prea[i],t2[i]=preb[i];
	}
	sort(t1,t1+n+1);sort(t2,t2+n+1);
	F(i,0,n)prea[i]=lower_bound(t1,t1+n+1,prea[i])-t1,preb[i]=lower_bound(t2,t2+n+1,preb[i])-t2;
	F(i,0,len-1)t[i]=++tot,id[i+1]=++cnt;
	F(i,0,n)prea[i]=n-prea[i],preb[i]=n-preb[i];
	Add(t[0],0,n,prea[0],preb[0],n);
	F(i,1,n){
		dp[i]=max(dp[i-1],Query(t[i%len],0,n,prea[i],preb[i])-n+i/len);//cerr<<prea[i]<<" "<<preb[i]<<endl;
		Add(t[i%len],0,n,prea[i],preb[i],dp[i]+n-i/len);
	}
	cout<<dp[n];//cerr<<endl<<Query(t[0],0,n,5,6)<<endl;
	return 0;
}
//prea[i]+i*ma<=prea[j]*j*ma