#include<bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define pb push_back
#define inf 0x3f3f3f3f
using namespace std;
const int N=2e5+5;
const int M=N*20;
int n,R,B,sb[N],p[N],f[N],sr[N],tot,ls[M],rs[M],mx[M],rt[N],a[N],b[N];
string str;
bool cmp(int x,int y){
	return a[x]>a[y];
}
int ins(int p,int l,int r,int x,int y){
	int q=++tot;
	ls[q]=ls[p],rs[q]=rs[p],mx[q]=max(mx[p],y);
	if(l==r)return q;
	int mid=l+r>>1;
	if(x<=mid)ls[q]=ins(ls[q],l,mid,x,y);
	else rs[q]=ins(rs[q],mid+1,r,x,y);
	return q;
}
int qry(int p,int l,int r,int ql,int qr){
	if(qr<l||ql>r||!p)return -inf;
	if(ql<=l&&r<=qr)return mx[p];
	int mid=l+r>>1;
	return max(qry(ls[p],l,mid,ql,qr),qry(rs[p],mid+1,r,ql,qr));
}
void cdq(int l,int r){
	if(l==r){
		if(l)f[l]=max(f[l],f[l-1]);
		return;
	}
	int mid=l+r>>1;
	cdq(l,mid);
	for(int i=l;i<=r;i++)p[i]=i;
	sort(p+l,p+mid+1,cmp);
	sort(p+mid+1,p+r+1,cmp);
	for(int i=l;i<=r;i++)rt[i%(R+B)]=0;
	for(int i=1;i<=tot;i++)ls[i]=rs[i]=mx[i]=0;tot=0;
	int i=l;
	for(int j=mid+1;j<=r;j++){
		while(i<=mid&&a[p[i]]>=a[p[j]]){
			//cout<<"add:"<<p[i]<<" "<<p[i]%(R+B)<<" "<<b[p[i]]<<" "<<f[p[i]]-p[i]/(R+B)<<"\n";
			rt[p[i]%(R+B)]=ins(rt[p[i]%(R+B)],-n,n,b[p[i]],f[p[i]]-p[i]/(R+B));
			i++;
		}
		//cout<<"qry:"<<p[j]<<" "<<p[j]%(R+B)<<" "<<b[p[j]]<<" "<<qry(rt[p[j]%(R+B)],-n,n,b[p[j]],n)<<"\n";
		f[p[j]]=max(f[p[j]],qry(rt[p[j]%(R+B)],-n,n,b[p[j]],n)+p[j]/(R+B));
	}
	cdq(mid+1,r);
}
int main(){
	//freopen("data.in","r",stdin);
	ios::sync_with_stdio(false);
	cin.tie(0),cout.tie(0);
	cin>>n>>R>>B>>str,mx[0]=-inf;
	for(int i=1;i<=n;i++){
		sb[i]=sb[i-1]+(str[i-1]=='B');
		sr[i]=sr[i-1]+(str[i-1]=='R');
		a[i]=sb[i]-i/(R+B)*B;
		b[i]=sr[i]-i/(R+B)*R;
		//cout<<a[i]<<" "<<b[i]<<"\n";
	}
	cdq(0,n); 
	cout<<f[n];
}