#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
using namespace std;
#define fi first
#define sc second
#define mkp make_pair
#define pii pair<int,int>
typedef long long ll;
const int N=2e5+5,oo=1e9;
inline int read() {
    int x=0,flag=0;char ch=getchar();
    while(ch<'0'||ch>'9') {flag|=(ch=='-');ch=getchar();}
    while('0'<=ch&&ch<='9') {x=(x<<3)+(x<<1)+ch-'0';ch=getchar();}
    return flag?-x:x;
}
inline int mx(int x,int y) {return x>y?x:y;}
inline int mn(int x,int y) {return x<y?x:y;}
inline void swp(int &x,int &y) {x^=y^=x^=y;}
inline int as(int x) {return x>0?x:-x;}

int n,r,b,k,sumr[N],sumb[N],lim,p[N],god,f[N];
vector<int> pos[N],v1[N],v2[N];
char s[N];
inline bool cmp(int x,int y) {return v1[god][x]<v1[god][y];}
struct Bit {
    int w[N<<1];
    inline void add(int x,int V) {
        x+=n+1;
        while(x<=2*n+2) {
            w[x]=mx(w[x],V);
            x+=x&-x;
        }
    }
    inline int query(int x) {
        int sum=-oo; x+=n+1;
        while(x) {
            sum=mx(sum,w[x]);
            x-=x&-x;
        }
        return sum;
    }
    inline void del(int x) {
        x+=n+1;
        while(x<=2*n+2) {
            w[x]=-oo;
            x+=x&-x;
        }
    }
}tr;
void solve(int l,int r) {
    if(l==r) return ;
    int mid=(l+r)>>1;
    solve(l,mid);
    for(int o=0;o<k;++o) {
        god=o;
        for(int i=l;i<=r;++i) p[i]=i,f[pos[o][i]]=mx(f[pos[o][i]],(pos[o][i]>0?f[pos[o][i]-1]:0));
        sort(p+l,p+mid+1,cmp);sort(p+mid+1,p+r+1,cmp);
        int ipos=l;
        for(int i=mid+1;i<=r;++i) {
            if(pos[o][p[i]]==0) continue;
            while(ipos<=mid&&v1[o][p[ipos]]<=v1[o][p[i]]) tr.add(v2[o][p[ipos]],f[pos[o][p[ipos]]]-p[ipos]),++ipos;
            f[pos[o][p[i]]]=mx(f[pos[o][p[i]]],tr.query(v2[o][p[i]])+p[i]);
        }
        for(int i=l;i<=mid;++i) tr.del(v2[o][i]);
    }
    solve(mid+1,r);
}
int main() {
    n=read();r=read();b=read();k=r+b;
    scanf("%s",s+1);
    for(int i=1;i<=n;++i) 
        sumr[i]=sumr[i-1]+(s[i]=='R'),
        sumb[i]=sumb[i-1]+(s[i]=='B');
    lim=n/k+1;
    for(int o=0;o<k;++o) {
        pos[o].resize(lim);v1[o].resize(lim);v2[o].resize(lim);
        for(int i=0;i*k+o<=n;++i)
            pos[o][i]=i*k+o;
        for(int i=1;i<lim;++i) {
            v1[o][i]=v1[o][i-1]+r-(sumr[pos[o][i]]-sumr[pos[o][i-1]]),
            v2[o][i]=v2[o][i-1]+b-(sumb[pos[o][i]]-sumb[pos[o][i-1]]);
        }
    }
    for(int i=1;i<=2*n;++i) tr.w[i]=-oo;
    solve(0,lim-1);
    printf("%d\n",f[n]);
    return 0;
}