#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <numeric>

using namespace std;

bool c(const string &s, int L, int k)
{
    int n = s.size();
    vector<int> ch(L, 0);
    for (int i = 0; i < n; ++i)
    {
        if (s[i] != s[i % L])
        {
            ++ch[i % L];
        }
    }
    int tot = accumulate(ch.begin(), ch.end(), 0);
    return tot <= k;
}

int f(const string &s, int k)
{
    int n = s.size();
    for (int L = 1; L <= n; ++L)
    {
        if (n % L == 0 && c(s, L, k))
        {
            return L;
        }
    }
    return n;
}

int main()
{
    int k;
    string s;
    cin >> k;
    cin >> s;
    cout << f(s, k) << endl;
    return 0;
}