#include <bits/stdc++.h>
using namespace std;
const int maxn = 50 + 9;
const long long inf = 1e8 + 2;
int Extgcd(int a, int b, int& x, int& y);
int main() {
  int n, p, q;
  while (~scanf("%d%d%d", &n, &p, &q)) {
    char aha[200];
    scanf("%s", aha);
    int x, y;
    int gg = Extgcd(p, q, x, y);
    if (n % gg != 0) {
      printf("-1\n");
      continue;
    }
    x *= n / gg, y *= n / gg;
    int tmp = q / gg;
    x = (x % tmp + tmp) % tmp;
    y = n - p * x;
    y /= q;
    if (y < 0) {
      printf("-1\n");
      continue;
    }
    int loca = 0;
    printf("%d\n", x + y);
    for (int i = 0; i < x; i++) {
      for (int j = 0; j < p; j++) printf("%c", aha[loca++]);
      printf("\n");
    }
    for (int i = 0; i < y; i++) {
      for (int j = 0; j < q; j++) printf("%c", aha[loca++]);
      printf("\n");
    }
  }
  return 0;
}
int Extgcd(int a, int b, int& x, int& y) {
  if (b == 0) {
    x = 1;
    y = 0;
    return a;
  } else {
    int ans = Extgcd(b, a % b, x, y);
    int t = x;
    x = y;
    y = t - (a / b) * y;
    return ans;
  }
}
