#include <bits/stdc++.h>
using namespace std;
struct node {
  long double pL, pR;
};
node combine(node fi, node se) {
  if (fi.pL == -1) return se;
  if (se.pL == -1) return fi;
  node res;
  res.pL = fi.pL * se.pL / (1 + (se.pL - 1) * fi.pR);
  res.pR = se.pR + ((1 - se.pR) * fi.pR * se.pL) / (1 - fi.pR * (1 - se.pL));
  return res;
}
const int N = 100100;
long double a[N], b[N];
node t[N * 4];
int n;
void build(int v, int l, int r) {
  if (l == r) {
    t[v] = {a[l] / b[l], a[l] / b[l]};
    return;
  }
  int mid = (l + r) >> 1;
  build(v + v, l, mid);
  build(v + v + 1, mid + 1, r);
  t[v] = combine(t[v + v], t[v + v + 1]);
}
void update(int v, int l, int r, int pos) {
  if (l == r) {
    t[v] = {a[l] / b[l], a[l] / b[l]};
    return;
  }
  int mid = (l + r) >> 1;
  if (pos <= mid)
    update(v + v, l, mid, pos);
  else
    update(v + v + 1, mid + 1, r, pos);
  t[v] = combine(t[v + v], t[v + v + 1]);
}
node get(int v, int l, int r, int tl, int tr) {
  if (l > r || tl > r || l > tr || tl > tr) return {-1, -1};
  if (tl <= l && r <= tr) {
    return t[v];
  }
  int mid = (l + r) >> 1;
  return combine(get(v + v, l, mid, tl, tr),
                 get(v + v + 1, mid + 1, r, tl, tr));
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int tt;
  cin >> n >> tt;
  for (int i = 1; i <= n; i++) {
    cin >> a[i] >> b[i];
  }
  build(1, 1, n);
  cout.precision(10);
  cout << fixed;
  while (tt--) {
    int type;
    cin >> type;
    if (type == 2) {
      int l, r;
      cin >> l >> r;
      cout << get(1, 1, n, l, r).pL << "\n";
    } else {
      int pos;
      cin >> pos;
      cin >> a[pos] >> b[pos];
      update(1, 1, n, pos);
    }
  }
}
