#include<bits/stdc++.h>
#define ll long long
using namespace std;
const int N=2e5+10,M1=N*18,M2=M1*18;
int n,r,b;
char s[N];
int v1[N],v2[N];
ll t1[N],t2[N];
int f[N];
int rt[N],tr[M1],mx[M2],tt1,tt2;
int ls[M1],rs[M1],lc[M2],rc[M2];
void upd2(int &o,int l,int r,int x,int v){
	if(!o)o=++tt2,mx[o]=-N;
	mx[o]=max(mx[o],v);
	if(l==r)return;
	int mid=l+r>>1;
	if(x<=mid)upd2(lc[o],l,mid,x,v);
	else upd2(rc[o],mid+1,r,x,v);
}
void upd1(int &o,int l,int r,int x,int y,int v){
	if(!o)o=++tt1;
	upd2(tr[o],0,n,y,v);
	if(l==r)return;
	int mid=l+r>>1;
	if(x<=mid)upd1(ls[o],l,mid,x,y,v);
	else upd1(rs[o],mid+1,r,x,y,v);
}
int qry2(int o,int l,int r,int x){
	if(!o)return -N;
	if(r<=x)return mx[o];
	int mid=l+r>>1;
	if(x<=mid)return qry2(lc[o],l,mid,x);
	return max(qry2(lc[o],l,mid,x),qry2(rc[o],mid+1,r,x));
}
int qry1(int o,int l,int r,int x,int y){
	if(!o)return -N;
	if(r<=x)return qry2(tr[o],0,n,y);
	int mid=l+r>>1;
	if(x<=mid)return qry1(ls[o],l,mid,x,y);
	return max(qry1(ls[o],l,mid,x,y),qry1(rs[o],mid+1,r,x,y));
}
signed main(){
	scanf("%d%d%d\n%s",&n,&r,&b,s+1);
	for(int i=1;i<=n;i++){
		v1[i]=v1[i-1]+(s[i]=='B');
		v2[i]=v2[i-1]+(s[i]=='R');
	}
	for(int i=1;i<=n;i++){
		t1[i]=v1[i]=-v1[i]+1ll*i*b/(r+b);
		t2[i]=v2[i]=-v2[i]+1ll*i*r/(r+b);
	}
	sort(t1,t1+n+1),sort(t2,t2+n+1);
	for(int i=0;i<=n;i++){
		v1[i]=lower_bound(t1,t1+n+1,v1[i])-t1;
		v2[i]=lower_bound(t2,t2+n+1,v2[i])-t2;
		if(i>=r+b)f[i]=max(f[i-1],qry1(rt[i%(r+b)],0,n,v1[i],v2[i])+i/(r+b));
		if(i+r+b<=n)upd1(rt[i%(r+b)],0,n,v1[i],v2[i],f[i]-i/(r+b));
	}
	printf("%d\n",f[n]);
}