#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")

#define rd_init() char*rp=({char*mmap();mmap(0l,1l<<25,1,2,0,0ll);})
#define rd() ({int _v=0,_c;while(_c=*rp++-48,_c>=0)_v=_v*10+_c;_v;})
#define wt(v) ({ulong _z=v;do*--wp=_z%10+48;while(_z/=10);})
#define wt1(v) ({char wbuf[64],*wp=wbuf+sizeof wbuf;wt(v);write(1,wp,wbuf+sizeof wbuf-wp);})
#define repeat(e) for(typeof(e)_=e;_--;)
#define min(a,b) (a<=b?a:b)
#define max(a,b) (a>=b?a:b)
#define chmin(v,a) (v=v<=a?v:a)

typedef unsigned long ulong;

int main(){
	rd_init();
	int n=rd();
	if(n&1){
		write(1,"-1",2);
		_exit(0);
	}
	int l=0;
	int d=0;
	repeat(n){
		*rp++&1?--d,chmin(l,d):++d;
	}
	char*s=rp++;
	long r=rd();
	long m=rd();
	long z=1l<<62;
	long t=0;
	long e=min(0,d)+1-l;
	repeat(n){
		long x=(max(0,e)&~1)*m+t;
		chmin(z,x);
		t+=r;
		*--s&1?++e:--e;
	}
	z+=(abs(d)>>1)*m;
	wt1(z);
	_exit(0);
}