#include <bits/stdc++.h>
using namespace std;
const int N = 1e3 + 5, OO = 0x3f3f3f3f, MOD = 1000000007;
const double EPS = 0.000000001;
long long sum;
long long n, m, c = 0, arr[2 * 10000 + 10], mn, mx;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int p, q, n;
  cin >> n >> p >> q;
  string s;
  cin >> s;
  int o = n / p;
  bool t = 0, b = 0;
  int i = o, l = 0, k = 0;
  while (l <= n && i >= 0) {
    if (n - p * i - q * l == 0) {
      t = 1;
      break;
    } else if (n - p * i - q * l > 0) {
      l++;
    } else if (n - p * i - q * l < 0) {
      i--;
    }
  }
  if (!t) {
    cout << -1;
  } else {
    cout << l + i << endl;
    for (int w = 0; w < i; w++) {
      for (int j = 0; j < p; j++) {
        cout << s[k], k++;
      }
      cout << endl;
    }
    for (int w = 0; w < l; w++) {
      for (int j = 0; j < q; j++) {
        cout << s[k], k++;
      }
      cout << endl;
    }
  }
}
