#include <bits/stdc++.h>
using namespace std;
inline void read(int &x) {
  int v = 0, f = 1;
  char c = getchar();
  while (!isdigit(c) && c != '-') c = getchar();
  if (c == '-')
    f = -1;
  else
    v = v * 10 + c - '0';
  while (isdigit(c = getchar())) v = v * 10 + c - '0';
  x = v * f;
}
inline void read(long long &x) {
  long long v = 0ll, f = 1ll;
  char c = getchar();
  while (!isdigit(c) && c != '-') c = getchar();
  if (c == '-')
    f = -1;
  else
    v = v * 10 + c - '0';
  while (isdigit(c = getchar())) v = v * 10 + c - '0';
  x = v * f;
}
inline void readc(char &x) {
  char c;
  while ((c = getchar()) == ' ')
    ;
  x = c;
}
inline void writes(string s) { puts(s.c_str()); }
inline void writeln() { writes(""); }
inline void writei(int x) {
  if (x < 0) {
    putchar('-');
    x = abs(x);
  }
  if (!x) putchar('0');
  char a[25];
  int top = 0;
  while (x) {
    a[++top] = (x % 10) + '0';
    x /= 10;
  }
  while (top) {
    putchar(a[top]);
    top--;
  }
}
inline void writell(long long x) {
  if (x < 0) {
    putchar('-');
    x = abs(x);
  }
  if (!x) putchar('0');
  char a[25];
  int top = 0;
  while (x) {
    a[++top] = (x % 10) + '0';
    x /= 10;
  }
  while (top) {
    putchar(a[top]);
    top--;
  }
}
int n, m, i, j, la, lb;
double a[2005], b[2005], l, r, mid, s1, s2;
struct ii {
  double s;
  int s1, s2;
} dp[2005];
set<int> ss;
void solve(double c1, double c2) {
  int i, j;
  for (((i)) = (1); ((i)) <= ((n)); ((i))++) {
    ii t = dp[i - 1];
    dp[i] = t;
    t = dp[i - 1];
    t.s += a[i] - c1;
    t.s1++;
    if (t.s > dp[i].s + 1e-10) dp[i] = t;
    t = dp[i - 1];
    t.s += b[i] - c2;
    t.s2++;
    if (t.s > dp[i].s + 1e-10) dp[i] = t;
    t = dp[i - 1];
    t.s += 1 - (1 - a[i]) * (1 - b[i]) - c1 - c2;
    t.s1++;
    t.s2++;
    if (t.s > dp[i].s + 1e-10) dp[i] = t;
  }
}
double lys(double x) {
  double l = 0, r = 1, mid;
  for (__typeof((ss).begin()) _ = (ss).begin(); _ != (ss).end(); _++) {
    mid = (l + r) / 2;
    solve(x, mid);
    if (dp[n].s2 > lb) {
      l = mid;
    } else {
      r = mid;
    }
  }
  return l;
}
int main() {
  srand(time(NULL));
  for (((i)) = (1); ((i)) <= ((50)); ((i))++)
    ss.insert(rand() % 32768 + rand());
  ios_base::sync_with_stdio(false);
  ;
  cin >> n >> la >> lb;
  for (((i)) = (1); ((i)) <= ((n)); ((i))++) {
    cin >> a[i];
  }
  for (((i)) = (1); ((i)) <= ((n)); ((i))++) {
    cin >> b[i];
  }
  l = 0;
  r = 1;
  for (__typeof((ss).begin()) _ = (ss).begin(); _ != (ss).end(); _++) {
    mid = (l + r) / 2;
    s1 = l;
    s2 = lys(mid);
    if (dp[n].s1 > la) {
      l = mid;
    } else {
      r = mid;
    }
  }
  solve(s1, s2);
  printf("%.10f\n", dp[n].s + s1 * la + s2 * lb);
  return 0;
}
