#include<bits/stdc++.h>
#define ll long long
using namespace std;
const int MAXN=2e5+5,inf=1e9;
int n,f[MAXN],R,B,c;
ll u[MAXN],v[MAXN];
char str[MAXN];
struct FenwickTree {
	int tr[MAXN],s;
	vector <int> e;
	void init() { fill(tr,tr+n+2,-inf); }
	void upd(int x,int w) {
		for(e.push_back(x);x<=n+1;x+=x&-x) tr[x]=max(tr[x],w);
	}
	int qry(int x) {
		for(s=-inf;x;x&=x-1) s=max(s,tr[x]);
		return s;
	}
	void clr() {
		for(int x:e) for(;x<=n+1;x+=x&-x) tr[x]=-inf;
		e.clear();
	}
}	T;
void cdq(int l,int r) {
	if(l==r) return ;
	int mid=(l+r)>>1;
	cdq(l,mid);
	for(int k=l;k<=mid&&k<l+c;++k) {
		vector <int> id;
		for(int i=k;i<=r;i+=c) id.push_back(i);
		stable_sort(id.begin(),id.end(),[&](int x,int y){ return v[x]<v[y]; });
		T.clr();
		for(int i:id) {
			if(i<=mid) T.upd(u[i],f[i]-i/c);
			else f[i]=max(f[i],T.qry(u[i])+i/c);
		}
	}
	for(int i=mid+1;i<=r;++i) f[i]=max(f[i],f[i-1]);
	cdq(mid+1,r);
}
signed main() {
	scanf("%d%d%d%s",&n,&R,&B,str+1),c=R+B;
	for(int i=1;i<=n;++i) {
		u[i]=u[i-1]+(str[i]=='B'?-R:B);
		v[i]=v[i-1]+(str[i]=='R'?-B:R);
	}
	vector <ll> Q(u,u+n+1);
	sort(Q.begin(),Q.end()),Q.erase(unique(Q.begin(),Q.end()),Q.end());
	for(int i=0;i<=n;++i) u[i]=lower_bound(Q.begin(),Q.end(),u[i])-Q.begin()+1;
    T.init(),cdq(0,n);
	printf("%d\n",f[n]);
	return 0;
}