#include <bits/stdc++.h>
using namespace std;
const int N = 1000 + 5;
int n, m;
int a[N], b[N];
double dp[N][N], q[N][N];
double solve() {
  for (int i = 0; i < n; i++) {
    for (int j = i + 1; j < n; j++) dp[i][j] = a[i] > a[j];
  }
  int x, y;
  while (m--) {
    scanf("%d%d", &x, &y);
    x--;
    y--;
    if (x > y) swap(x, y);
    for (int i = x + 1; i < y; i++) {
      q[x][i] = 0.5 * dp[x][i] + 0.5 * (1.0 - dp[i][y]);
      q[i][y] = 0.5 * dp[i][y] + 0.5 * (1.0 - dp[x][i]);
    }
    for (int i = 0; i < x; i++) {
      q[i][x] = 0.5 * dp[i][x] + 0.5 * dp[i][y];
      q[i][y] = 0.5 * dp[i][y] + 0.5 * dp[i][x];
    }
    for (int i = y + 1; i < n; i++) {
      q[x][i] = 0.5 * dp[x][i] + 0.5 * dp[y][i];
      q[y][i] = 0.5 * dp[y][i] + 0.5 * dp[x][i];
    }
    q[x][y] = 0.5 * dp[x][y] + 0.5 * (1 - dp[x][y]);
    for (int i = x + 1; i < y; i++) {
      dp[x][i] = q[x][i];
      dp[i][y] = q[i][y];
    }
    dp[x][y] = q[x][y];
    for (int i = 0; i < x; i++) {
      dp[i][x] = q[i][x];
      dp[i][y] = q[i][y];
    }
    for (int i = y + 1; i < n; i++) {
      dp[x][i] = q[x][i];
      dp[y][i] = q[y][i];
    }
  }
  double ans = 0;
  for (int i = 0; i < n; i++)
    for (int j = i + 1; j < n; j++) ans += dp[i][j];
  return ans;
}
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 0; i < n; i++) scanf("%d", &a[i]);
  printf("%.10f\n", solve());
  return 0;
}
