#include <bits/stdc++.h>
static inline void setio(void);
int main(void) {
  setio();
  long long n, k;
  std::cin >> n >> k;
  std::string t;
  std::cin >> t;
  std::string s = t;
  long long max = 0;
  for (long long pos = 1; pos < n; ++pos) {
    std::string sub1 = t.substr(0, pos);
    std::string sub2 = s.substr(n - pos);
    if (sub1 == sub2) max = pos;
  }
  for (long long i = 1; i < k; ++i) {
    s += t.substr(max);
  }
  std::cout << s << "\n";
  return 0;
}
static inline void setio(void) {
  std::ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  std::cout.precision(10);
  std::cout << std::fixed;
}
