#include <bits/stdc++.h>
using namespace std;
int main(){
	int n;
	cin>>n;
	string polje;
	cin>>polje;
	int j=n-1;
	for(int i=0; i<n; i++)
	{
		if(j==i+1 and polje[j]==polje[i])
		{
			cout<<n-((n-1-j)*2+2);
			break;
		}
		if(j==i)
		{
			cout<<n-((n-1-j)*2+1);
			break;
		}
		if(polje[i]==polje[j])
		{
			j--;
		}
		else if(j!=n-1)
		{
			j=n-1;
			i--;
		}
		else
		{
			j=n-1;
		}
	}
	return 0;
}