``#include #include using namespace std;

int main() { int k; string s; cin >> k >> s;

int n = s.length();
int count = 1; // 当前字符连续出现的次数

for (int i = 1; i <= n; i++) {
    if (i < n && s[i] == s[i-1]) {
        count++;
    } else {
        // 当前连续段结束
        if (count >= k) {
            cout << s[i-1] << endl;
            return 0;
        }
        count = 1;
    }
}

cout << "No" << endl;

return 0;

}******