N1305 - 광고

import java.io.InputStreamReader;
import java.io.BufferedReader;
import java.io.IOException;

public class N1305 {
    private static final BufferedReader BR = new BufferedReader(new InputStreamReader(System.in));
    static String paragraph;
    static int n;

    public static void main(String[] args) throws IOException{
        n = Integer.parseInt(BR.readLine());
        paragraph = BR.readLine();
        System.out.print(n - getFailureScores(paragraph)[n-1]);
    }

    static int[] getFailureScores(String pattern) {
        int[] table = new int[pattern.length()];
        int j = 0;

        for (int i = 1; i < table.length; i++) {
            while (j > 0 && pattern.charAt(j) != pattern.charAt(i))
                j = table[j-1];

            if (pattern.charAt(i) == pattern.charAt(j))
                table[i] = ++j;
        }

        return table;
    }
}