#include<cstdio>

#define ll long long

#define r register int

#define MN (1<<20)

#define MOD 1000000007

char s[MN+];

int n,ans,f[MN+];

ll a[MN+];

inline int mod(int x){return x<MOD?x:x-MOD;}

void fwt(int v)

{

    for(r i=;i<n;++i)for(r j=,x;j<<<n;++j)if(x=j^(<<i),j&(<<i))

        a[x]=a[x]+a[j],a[j]=(a[x]-a[j]-a[j])/(v?:),a[x]/=v?:;

}

int main()

{

    scanf("%d%s",&n,s);

    for(r i=;i<<<n;++i)a[i]=s[i]-'';fwt();

    for(r i=;i<<<n;++i)a[i]*=a[i];fwt();

    for(r i=f[]=;i<<<n;++i)f[i]=mod(f[i>>]<<(i&));

    for(r i=;i<<<n;++i)ans=(ans+1LL*a[i]*f[i^((<<n)-)])%MOD;

    printf("%d",3LL*ans%MOD);

}