#include<iostream>
#include<string>
#include <vector>
#include <algorithm>
#define rep(i,a,n) for (int i=(a);i<(n);i++)

using namespace std;

int n;
string s;

int main()
{
	cin>>n;
	cin>>s;
	
	reverse(s.begin(),s.end());

	vector<int> p[2] = {vector<int>(n+1),vector<int>(n)};
	rep(z,0,2) for (int i=0,l=0,r=0;i<n;i++)
	{
		int t= r-i+!z;
		if(i<r) p[z][i] = min(t,p[z][l+t]);
		int L = i-p[z][i], R = i+p[z][i]-!z;
		while(L>=1 && R+1 < n && s[L-1] == s[R+1])
			p[z][i]++,L--,R++;
		if(R>r) l=L,r=R;
	}


	//for(int i=0;i<n;i++)
	//	std::cout << p[0][i] << " ";
	//std::cout << std::endl;
	//for(int i=0;i<n;i++)
//		std::cout << p[1][i] << " ";
//	std::cout << std::endl;


	int mn=n;
	for(int i=0;i<n;i++)
	{
		if(p[0][i] == i)
		{
			mn = n-2*i;
		}
		if(p[1][i] == i)
		{
			mn = n-2*i-1;
		}	
	}

	std::cout << mn << std::endl;
}