#include <bits/stdc++.h>
using namespace std;
double dp[1010][1010];
int a[1010], n, m;
void init() {
  for (int i = 1; i <= n; i++)
    for (int j = i + 1; j <= n; j++)
      if (a[i] > a[j]) dp[i][j] = 1;
}
int main() {
  scanf("%d %d", &n, &m);
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
  init();
  for (int i = 1; i <= m; i++) {
    int l, r;
    scanf("%d %d", &l, &r);
    if (l > r) swap(l, r);
    for (int j = 1; j < l; j++) {
      double pom = 0.5 * dp[j][l] + 0.5 * dp[j][r];
      dp[j][l] = pom;
      dp[j][r] = pom;
    }
    for (int j = r + 1; j <= n; j++) {
      double pom = 0.5 * dp[l][j] + 0.5 * dp[r][j];
      dp[l][j] = pom;
      dp[r][j] = pom;
    }
    for (int j = l + 1; j < r; j++) {
      double pom = 0.5 * dp[j][r] + 0.5 * (1 - dp[l][j]);
      double pom2 = 0.5 * dp[l][j] + 0.5 * (1 - dp[j][r]);
      dp[j][r] = pom;
      dp[l][j] = pom2;
    }
    dp[l][r] = 0.5;
  }
  double rez = 0;
  for (int i = 1; i <= n; i++)
    for (int j = i + 1; j <= n; j++) rez += dp[i][j];
  cout << fixed << setprecision(8) << rez << endl;
  return 0;
}
