#include <bits/stdc++.h>
using namespace std;
inline bool isvowel(char c) {
  c = tolower(c);
  if (c == 'a' || c == 'e' || c == 'i' || c == 'y' || c == 'o' || c == 'u')
    return 1;
  return 0;
}
const double eps = 0.000001;
const long double pi = acos(-1);
const int maxn = 1e7 + 9;
const int mod = 1e9 + 7;
const long long MOD = 1e18 + 9;
const long long INF = 1e18 + 123;
const int inf = 2e9 + 11;
const int mxn = 1e6 + 9;
const int N = 1123;
const int M = 22;
const int pri = 997;
const int Magic = 2101;
const int dx[] = {-1, 0, 1, 0};
const int dy[] = {0, -1, 0, 1};
int n, m;
int a[N];
double dp[N][N];
int main() {
  cin >> n >> m;
  for (int i = 1; i <= n; ++i) cin >> a[i];
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= n; j++)
      if (a[i] < a[j]) dp[j][i] = 1.0;
  }
  for (int i = 1; i <= m; i++) {
    int x, y;
    cin >> x >> y;
    dp[x][y] = 0.5;
    dp[y][x] = 0.5;
    for (int v = 1; v <= n; v++) {
      if (v == x || v == y) continue;
      dp[v][x] = dp[v][y] = (dp[v][x] + dp[v][y]) * (double)0.5;
    }
    for (int v = 1; v <= n; v++) {
      if (v == x || v == y) continue;
      dp[x][v] = 1.0 - dp[v][x];
      dp[y][v] = 1.0 - dp[v][y];
    }
  }
  double ans = 0.0;
  for (int i = 1; i <= n; i++)
    for (int j = i + 1; j <= n; j++) ans += dp[i][j];
  cout << fixed << setprecision(12) << ans;
  return 0;
}
