ll n,m;string s[1d3];
ll f(string t){
	ll z=0;
	rep(i,n){
		ll j=0,k=0,v;
		for(;v=t[j+k];)v-s[i][j]?++k:++j;
		z|=v|k-1;
	}
	return!z;
}
{
	rd(n,m,s(n));
	ll j=argmax[i,0,m]((s[0][i]!=s[1][i]));
	Wt(f(s[0].substr(0,j+1)+s[1].substr(j))+f(s[1].substr(0,j+1)+s[0].substr(j)));
}