#include <bits/stdc++.h>
using namespace std;
const int inf = 0x20202020;
const int mod = 1000000007;
template <class T>
inline void read(T& x) {
  bool fu = 0;
  char c;
  for (c = getchar(); c <= 32; c = getchar())
    ;
  if (c == '-') fu = 1, c = getchar();
  for (x = 0; c > 32; c = getchar()) x = x * 10 + c - '0';
  if (fu) x = -x;
};
template <class T>
inline void read(T& x, T& y) {
  read(x);
  read(y);
}
template <class T>
inline void read(T& x, T& y, T& z) {
  read(x);
  read(y);
  read(z);
}
template <class T>
inline void read(T& x, T& y, T& z, T& q) {
  read(x);
  read(y);
  read(z);
  read(q);
}
const int DX[] = {1, 0, -1, 0}, DY[] = {0, 1, 0, -1};
long long powmod(long long a, long long b) {
  long long res = 1;
  a %= mod;
  for (; b; b >>= 1) {
    if (b & 1) res = res * a % mod;
    a = a * a % mod;
  }
  return res;
}
long long powmod(long long a, long long b, long long mod) {
  long long res = 1;
  a %= mod;
  for (; b; b >>= 1) {
    if (b & 1) res = res * a % mod;
    a = a * a % mod;
  }
  return res;
}
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
const int N = 1111, M = 111111;
int l, m, n, t, C, a[N], x, y;
double f[N][N];
int main() {
  scanf("%d%d", &n, &m);
  for (int _tmp = n, i = 1; i <= _tmp; ++i) scanf("%d", &a[i]);
  for (int _tmp = n, i = 1; i <= _tmp; ++i)
    for (int _tmp = n, j = 1; j <= _tmp; ++j)
      if (i != j) f[i][j] = double(a[i] > a[j]);
  for (int _tmp = m, _ = 1; _ <= _tmp; ++_) {
    scanf("%d%d", &x, &y);
    for (int _tmp = n, i = 1; i <= _tmp; ++i)
      if (i != x && i != y) {
        f[i][x] = f[i][y] = (f[i][x] + f[i][y]) / 2;
        f[x][i] = f[y][i] = (f[x][i] + f[y][i]) / 2;
      }
    f[x][y] = f[y][x] = 0.5;
  }
  double ans = 0;
  for (int _tmp = n, i = 1; i <= _tmp; ++i)
    for (int _tmp = n, j = i + 1; j <= _tmp; ++j) ans += f[i][j];
  printf("%.9lf\n", ans);
  return 0;
}
