#include <bits/stdc++.h>
using namespace std;
const int N = 100100;
pair<double, double> tree[4 * N];
double p[N];
int n, q;
pair<double, double> mer(pair<double, double> a, pair<double, double> b) {
  pair<double, double> ans;
  ans.first = a.first * b.first / (1 - a.second + a.second * b.first);
  ans.second = b.second + (1 - b.second) * a.second * b.first /
                              (1 - a.second + a.second * b.first);
  return ans;
}
void buildTree(int s, int l, int r) {
  if (l == r) {
    tree[s].first = tree[s].second = p[l];
    return;
  }
  int mid = (l + r) >> 1;
  buildTree(2 * s, l, mid);
  buildTree(2 * s + 1, mid + 1, r);
  tree[s] = mer(tree[2 * s], tree[2 * s + 1]);
}
void update(int s, int l, int r, int u, double w) {
  if (l > u || r < u) return;
  if (l == r) {
    tree[s].first = tree[s].second = w;
    return;
  }
  int mid = (l + r) >> 1;
  update(2 * s, l, mid, u, w);
  update(2 * s + 1, mid + 1, r, u, w);
  tree[s] = mer(tree[2 * s], tree[2 * s + 1]);
}
pair<double, double> get(int s, int l, int r, int u, int v) {
  if (r < u || l > v) return make_pair(1, 0);
  if (u <= l && r <= v) return tree[s];
  int mid = (l + r) >> 1;
  pair<double, double> t1 = get(2 * s, l, mid, u, v);
  pair<double, double> t2 = get(2 * s + 1, mid + 1, r, u, v);
  return mer(t1, t2);
}
int main() {
  ios_base::sync_with_stdio(false);
  cin >> n >> q;
  for (int i = 1; i <= n; i++) {
    int a, b;
    cin >> a >> b;
    p[i] = 1.0 * a / b;
  }
  buildTree(1, 1, n);
  for (int i = 1; i <= q; i++) {
    int type, l, r, v;
    cin >> type;
    if (type == 1) {
      cin >> v >> l >> r;
      update(1, 1, n, v, 1.0 * l / r);
    } else {
      cin >> l >> r;
      pair<double, double> ans = get(1, 1, n, l, r);
      cout << fixed << setprecision(8) << ans.first << endl;
    }
  }
  return 0;
}
