#include <bits/stdc++.h>
using namespace std;
const int MAX = 1e5 + 5;
const long double EPS = 1e-12;
long double arr[MAX], u[MAX], p[MAX];
pair<long double, long double> st[4 * MAX];
int n;
inline pair<long double, long double> merge(pair<long double, long double> f,
                                            pair<long double, long double> s) {
  pair<long double, long double> ans;
  ans.first = f.first * s.first;
  ans.second = f.second + s.second * f.first;
  return ans;
}
void build(int id, int l, int r) {
  if (l == r) {
    st[id] = make_pair(u[l], u[l]);
    return;
  }
  build(id * 2, l, (l + r) / 2);
  build(id * 2 + 1, (l + r) / 2 + 1, r);
  st[id] = merge(st[id * 2], st[id * 2 + 1]);
}
void update(int id, int l, int r, int idx) {
  if (l == r && l == idx) {
    st[id] = make_pair(u[l], u[l]);
    return;
  }
  if (idx > r || l > idx) {
    return;
  }
  int mid = (l + r) / 2;
  update(id * 2, l, mid, idx);
  update(id * 2 + 1, mid + 1, r, idx);
  st[id] = merge(st[id * 2], st[id * 2 + 1]);
}
pair<long double, long double> query(int id, int l, int r, int i, int j) {
  if (l >= i && j >= r) {
    return st[id];
  }
  if (i > r || l > j) {
    return make_pair(1.0, 0.0);
  }
  int mid = (l + r) / 2;
  auto q1 = query(id * 2, l, mid, i, j);
  auto q2 = query(id * 2 + 1, mid + 1, r, i, j);
  auto ret = merge(q1, q2);
  return ret;
}
int main() {
  int q;
  scanf("%d %d", &n, &q);
  for (int i = int(1); i < int(n + 1); i++) {
    int a, b;
    scanf("%d %d", &a, &b);
    p[i] = (long double)a / (long double)b;
    u[i] = (1 - p[i]) / p[i];
  }
  build(1, 1, n);
  for (int i = int(1); i < int(q + 1); i++) {
    int type;
    scanf("%d", &type);
    if (type == 1) {
      int id, a, b;
      scanf("%d %d %d", &id, &a, &b);
      p[id] = (long double)a / (long double)b;
      u[id] = (1 - p[id]) / p[id];
      update(1, 1, n, id);
    } else {
      int l, r;
      scanf("%d %d", &l, &r);
      long double cur = query(1, 1, n, l, r).second;
      long double ans = 0.0;
      if (cur < 1e30) {
        ans = 1.0 / (1.0 + cur);
      }
      printf("%.10Lf\n", ans);
    }
  }
  return 0;
}
