#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<stdlib.h>
#include<algorithm>
using namespace std;
const int MAXN=20;
int a[MAXN],b[MAXN],num[MAXN],temp[MAXN],ans;
void swap(int &a,int &b)
{int temp;temp=a;a=b;b=temp;
}
int min(int a,int b)
{if(a>b) return b;else return a;
}
int main()
{int n,m,num0=0,num1=0,res1=0,res2=0;int minn=0x3f3f3f3f;scanf("%d %d",&n,&m);for(int i=1;i<=n;i++){scanf("%d",&a[i]);if(a[i]==1) num1++;if(a[i]==0) num0++;}for(int i=1;i<=m;i++){scanf("%d",&temp[i]);if(i%2==1) res1+=temp[i];if(i%2==0) res2+=temp[i];}if(res1==num1){ans=0;memset(b,0,sizeof(b));for(int i=1;i<=n;i++) num[i]=a[i];int flag=1,cnt=1;for(int i=1;i<=m;i++){for(int j=1;j<=temp[i];j++)b[cnt++]=flag;flag=!flag;}for(int i=1;i<=n;i++){if(num[i]==b[i]) continue;else{for(int j=i+1;j<=n;j++){if(b[j]==!b[i]){swap(b[j],b[i]);ans+=j-i;break;}}}}minn=min(ans,minn);}if(res1==num0){ans=0;memset(b,0,sizeof(b));for(int i=1;i<=n;i++) num[i]=a[i];int flag=0,cnt=1;for(int i=1;i<=m;i++){for(int j=1;j<=temp[i];j++)b[cnt++]=flag;flag=!flag;}for(int i=1;i<=n;i++){if(num[i]==b[i]) continue;else{for(int j=i+1;j<=n;j++){if(b[j]==!b[i]){swap(b[j],b[i]);ans+=j-i;break;}}}}minn=min(ans,minn);}printf("%d\n",minn);return 0;
}

#include <algorithm>
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <vector>
#include <map>
#define N 1000005
#define lson o<<1, l, m
#define rson o<<1|1, m + 1, r
#define mod 1000000007
using namespace std;
typedef long long LL;int n,m;
int vis[100050];
int a[20],b[20],c[20];
int ans[2];
int st;int bfs()
{int pre[100005];int begin = 0,end = 1;pre[0] = st;int t[100006];t[0] = 0;while(begin < end){int w = pre[begin];if(w == ans[0] || w == ans[1]){return t[begin];}int i;int g = 1;int now;for(i = 0; i < n - 1; i++){if(((w >> i) & 1) != ((w >>(i + 1)) & 1)){if(((w >> i) & 1) == 1){now = w + g;}else{now = w - g;}if(vis[now] == 0){vis[now] = 1;pre[end] = now;t[end++] = t[begin] + 1;}}g *= 2;}begin++;}
}
int main()
{while(scanf("%d %d",&n,&m)!=EOF){int i,j;st = 0;for(i = 0; i < n; i++){scanf("%d",&a[i]);}int g = 1;for(i = n - 1; i >= 0; i--){st += a[i] * g;g *= 2;}for(i = 0; i < m; i++){scanf("%d",&b[i]);}g = 0;j = 0;for(i = 0; i < m; i++){for(int k = 0; k < b[i]; k++){c[j++] = g;}g ^= 1;}ans[0] = ans[1] = 0;g = 1;for(i = n - 1; i >= 0; i--){ans[0] += c[i] * g;g *= 2;}g = 1;j = 0;for(i = 0; i < m; i++){for(int k = 0; k < b[i]; k++){c[j++] = g;}g ^= 1;}g = 1;for(i = n - 1; i >= 0; i--){ans[1] += c[i] * g;g *= 2;}        memset(vis,0,sizeof(vis));printf("%d\n",bfs());}return 0;
}