#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
const int N=2e5+5;
int n,r,b,k;char s[N];
int sr[N],sb[N];
ll v1[N],v2[N];int V=0,d[N];

inline void ckmx(int&x,int y){x<y&&(x=y);}
const int INF=0x3f3f3f3f;
int tr[N];
inline void U(int p,int k){for(;p<=V;p+=p&-p)ckmx(tr[p],k);}
inline int Q(int p){int r=-INF;for(;p;p^=p&-p)ckmx(r,tr[p]);return r;}
inline void del(int p){for(;p<=V;p+=p&-p)tr[p]=-INF;}
int dp[N];
void cdq(int l,int r){
	if(l==r)return;
	int mid=l+r>>1;cdq(l,mid);
	for(int o=0;o<k&&l+o<=mid;o++){
		basic_string<int>id;
		for(int i=l+o;i<=r;i+=k)id+=i;
		stable_sort(id.begin(),id.end(),[&](int x,int y){return v2[x]<v2[y];});
		for(int i:id)
			if(i<=mid)U(v1[i],dp[i]-i/k);
			else ckmx(dp[i],Q(v1[i])+i/k);
		for(int i:id)if(i<=mid)del(v1[i]);
	}
	for(int i=mid+1;i<=r;i++)ckmx(dp[i],dp[i-1]);
	cdq(mid+1,r);
}
int main(){
	scanf("%d%d%d%s",&n,&r,&b,s+1);k=r+b;
	for(int i=1;i<=n;i++){
		v1[i]=v1[i-1]+(s[i]=='B'?-r:b);
		v2[i]=v2[i-1]+(s[i]=='R'?-b:r);
		d[i]=v1[i];
	}
	d[V=n+1]=0;sort(d+1,d+V+1);V=unique(d+1,d+V+1)-d-1;
	for(int i=0;i<=n;i++)v1[i]=lower_bound(d+1,d+V+1,v1[i])-d;
	memset(tr,0xc0,sizeof tr);cdq(0,n);
	printf("%d\n",dp[n]);
	return 0;
}