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#include<bits/stdc++.h>
#define fi first
#define se second
using namespace std;
const int N=8;
bool tab[N+2][N+2];
long long choose[N*N+10][N*N+10];
long long solve2(int n,int k,int s)
{
	long long ans=0;
	for(int msk1=0;msk1<(1<<n);msk1++)
	{
		for(int msk2=0;msk2<(1<<n);msk2++)
		{
			int cnt=__builtin_popcount(msk1)+__builtin_popcount(msk2);
			if(cnt>k || 2*n-cnt>s-k)
				continue;
			ans+=2*__builtin_popcount(msk1&msk2)*choose[s-2*n][k-cnt];
		}
	}
	return ans;
}
long long solve1(int n,int k,int s)
{
	long long ans=0;
	for(int msk1=0;msk1<(1<<n);msk1++)
	{
		int cnt=__builtin_popcount(msk1);
		if(cnt>k || n-cnt>s-k)
			continue;
		ans+=cnt*choose[s-n][k-cnt];
	}
	return ans;
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	for(int i=0;i<=N*N;i++)
	{
		choose[i][0]=1;
		for(int j=1;j<=i;j++)
			choose[i][j]=choose[i-1][j-1]+choose[i-1][j];
	}
	int n,m,k=0;
	cin>>n>>m;
	int mod2=0,mod22=0;
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=m;j++)
		{
			char c;
			cin>>c;
			if(c=='O')
			{
				mod2=(mod2+i+j)%2;
				k++;
			}
		}
	}
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=m;j++)
		{
			char c;
			cin>>c;
			if(c=='O')
			{
				mod22=(mod22+i+j)%2;
				tab[i][j]=true;
			}
		}
	}
	if(mod2!=mod22)
	{
		cout<<"0\n";
		return 0;
	}

	int nom=0;
	for(int i=1;i<=n;i++)
		tab[i][0]=tab[i][m+1]=true;
	for(int i=1;i<=m;i++)
		tab[0][i]=tab[n+1][i]=true;
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=m;j++)
		{
			if(!tab[i][j])
				continue;
			nom+=4;
			nom-=tab[i][j-1];
			nom-=tab[i][j+1];
			nom-=tab[i-1][j];
			nom-=tab[i+1][j];
		}
	}

	long long den=4*k*choose[n*m][k];
	//cerr<<den<<"\n";
	den-=solve2(n,k,n*m)*(m-1);
	//cerr<<den<<"\n";
	den-=solve2(m,k,n*m)*(n-1);
	//cerr<<den<<"\n";
	den-=solve1(n,k,n*m)*2;
	//cerr<<den<<"\n";
	den-=solve1(m,k,n*m)*2;
	//cerr<<den<<"\n";
	den/=2;

	//cerr<<nom<<"/"<<den<<"\n";
	cout<<fixed<<setprecision(15)<<(long double)nom/den<<"\n";
	return 0;
}