#include <bits/stdc++.h>
using namespace std;
constexpr int SIZE = 131072;
double stree1[SIZE * 2 + 1], stree2[SIZE * 2 + 1];
void update_internal(int pos) {
  int child1 = pos << 1;
  int child2 = child1 + 1;
  double a = stree1[child1];
  double b = stree2[child1];
  double c = stree1[child2];
  double d = stree2[child2];
  stree1[pos] = a * c / (1 - (1 - b) * (1 - c));
  stree2[pos] = b * d / (1 - (1 - b) * (1 - c));
}
void update(int pos, int a, int b) {
  pos += SIZE;
  stree1[pos] = (double)a / b;
  stree2[pos] = (double)(b - a) / b;
  for (pos >>= 1; pos >= 1; pos >>= 1) {
    update_internal(pos);
  }
}
double query(int l, int r) {
  vector<pair<double, double>> vt1, vt2;
  l += SIZE;
  r += SIZE;
  while (l <= r) {
    if (l & 1) {
      vt1.emplace_back(stree1[l], stree2[l]);
      l++;
    }
    if ((r & 1) == 0) {
      vt2.emplace_back(stree1[r], stree2[r]);
      r--;
    }
    l >>= 1;
    r >>= 1;
  }
  vt1.insert(vt1.end(), vt2.rbegin(), vt2.rend());
  while (vt1.size() >= 2) {
    auto right = vt1.back();
    vt1.pop_back();
    auto left = vt1.back();
    vt1.pop_back();
    double a = left.first;
    double b = left.second;
    double c = right.first;
    double d = right.second;
    vt1.emplace_back(a * c / (1 - (1 - b) * (1 - c)),
                     b * d / (1 - (1 - b) * (1 - c)));
  }
  return vt1[0].first;
}
int main() {
  int n, q;
  scanf("%d%d", &n, &q);
  for (int i = 0; i < n; i++) {
    int a, b;
    scanf("%d%d", &a, &b);
    stree1[i + SIZE] = (double)a / b;
    stree2[i + SIZE] = (double)(b - a) / b;
  }
  for (int i = n; i < SIZE; i++) {
    stree1[i] = 1;
    stree2[i] = 0;
  }
  for (int i = SIZE - 1; i >= 1; i--) update_internal(i);
  for (int i = 0; i < q; i++) {
    int type;
    scanf("%d", &type);
    if (type == 1) {
      int idx, a, b;
      scanf("%d%d%d", &idx, &a, &b);
      idx--;
      update(idx, a, b);
    } else {
      int l, r;
      scanf("%d%d", &l, &r);
      l--;
      r--;
      printf("%.9f\n", query(l, r));
    }
  }
}
