#include<bits/stdc++.h>
using namespace std;
#define ll long long
const int N=2.2e6;
char c[N];
int a[N],n,b[N];
int C(int n,int k)
{
	if((n&k)==k)return 1;return 0;
 } 
int main()
{//cout<<C(5,0)<<endl;
	cin>>n;scanf("%s",c+1);
	for(int i=1;i<=n;i++)a[i]=c[i]-'0';int fg=0;n--;
	for(int i=1;i<=n;i++){
		b[i]=abs(a[i]-a[i+1]);
		if(b[i]==1)fg=1;
	}int ans=0;
	if(fg)
	{
		for(int i=1;i<=n;i++)b[i]=b[i]%2;
		for(int i=1;i<=n;i++)ans=ans^(C(n-1,i-1)*b[i]);
		cout<<ans;
		return 0;
	}
	for(int i=1;i<=n;i++)b[i]=b[i]/2;
	//for(int i=1;i<=n;i++)cout<<b[i]<<" ";puts("");
	for(int i=1;i<=n;i++)ans=ans^(C(n-1,i-1)*b[i]);
	cout<<ans*2;
}
