#include<bits/stdc++.h>
using namespace std;
#define ll long long
namespace IO{//by cyffff
	int len=0;
	char ibuf[(1<<21)+1],*iS,*iT,out[(1<<25)+1];
	#if ONLINE_JUDGE
	#define gh() (iS==iT?iT=(iS=ibuf)+fread(ibuf,1,(1<<21)+1,stdin),(iS==iT?EOF:*iS++):*iS++)
 	#else
	#define gh() getchar()
	#endif
	#define reg register
	inline int read(){
		reg char ch=gh();
		reg int x=0;
		reg char t=0;
		while(ch<'0'||ch>'9')   t|=ch=='-',ch=gh();
		while(ch>='0'&&ch<='9') x=x*10+(ch^48),ch=gh();
		return t?-x:x;
	}
	inline void putc(char ch){
		out[len++]=ch;
	}
	template<class T>
	inline void write(T x){
		if(x<0)putc('-'),x=-x;
		if(x>9)write(x/10);
		out[len++]=x%10+48;
	}
	inline void flush(){
		fwrite(out,1,len,stdout);
		len=0;
	}
	inline char getc(){
		char ch=gh();
		while(ch<'A'||ch>'Z') ch=gh();
		return ch;
	}
}
using IO::read;
using IO::write;
using IO::flush;
using IO::getc;
using IO::putc;
const int N=2e5+10;
int n,a,b,c,col[N],pr1[N],pr2[N],ps[N],f[N];
inline bool cmp(int x,int y){
	return pr1[x]<pr1[y];
}
struct BIT{
	#define lowbit(x) (x&-x)
	vector<int>t;
	int n;
	inline void set(int N){
		n=N,t.resize(n+1,-1e9);
	}
	inline void add(int x,int v){
		for(int i=x;i<=n;i+=lowbit(i))
			t[i]=max(t[i],v); 
	}
	inline void clear(int x){
		for(int i=x;i<=n;i+=lowbit(i))
			t[i]=-1e9; 
	}
	inline int query(int x){
		int s=-1e9;
		for(int i=x;i;i-=lowbit(i))
			s=max(s,t[i]);
		return s;
	}
}T[N];
inline void CDQ(int l,int r){
	if(l==r){
		f[l+1]=max(f[l+1],f[l]);
		return ;
	}
	int mid=l+r>>1;
	CDQ(l,mid);
	sort(ps+l,ps+mid+1,cmp);
	sort(ps+mid+1,ps+r+1,cmp);
	int p=l,q=mid+1;
	while(p<=mid&&q<=r){
		if(pr1[ps[p]]<=pr1[ps[q]]) T[ps[p]%c].add(pr2[ps[p]],f[ps[p]]-ps[p]/c),p++;
		else f[ps[q]]=max(f[ps[q]],T[ps[q]%c].query(pr2[ps[q]])+ps[q]/c),q++;
	}
	while(q<=r)
		f[ps[q]]=max(f[ps[q]],T[ps[q]%c].query(pr2[ps[q]])+ps[q]/c),q++;
	while(p>=l)
		T[ps[p]%c].clear(pr2[ps[p]]),p--;
	for(int i=mid+1;i<=r;i++)
		ps[i]=i;
	CDQ(mid+1,r);
}
int main(){
	n=read(),a=read(),b=read(),c=a+b;
	for(int i=1;i<=n;i++){
		char c=getc();
		if(c=='R') col[i]=1;
		if(c=='B') col[i]=2;
	}
	for(int i=1;i<=n;i++)
		pr1[i]=pr1[i-1]+(col[i]==1),
		pr2[i]=pr2[i-1]+(col[i]==2);
	for(int i=1;i<=n;i++)
		pr1[i]=i/c*a-pr1[i],
		pr2[i]=i/c*b-pr2[i];
	
	for(int i=0;i<c;i++){
		vector<int>vec;
		for(int j=i;j<=n;j+=c)
			vec.push_back(pr2[j]);
		sort(vec.begin(),vec.end());
		vec.erase(unique(vec.begin(),vec.end()),vec.end());
		for(int j=i;j<=n;j+=c)
			pr2[j]=lower_bound(vec.begin(),vec.end(),pr2[j])-vec.begin()+1;
		T[i].set(vec.size());
	}
	for(int i=1;i<=n;i++)
		ps[i]=i;
	CDQ(0,n);
	write(f[n]);
	flush();
}