#include <bits/stdc++.h>
using namespace std;
const int Maxn = 100000;
int N;
double T[Maxn + 5];
struct SegmentTree {
  struct Segment {
    double mul, sum;
  };
  Segment t[Maxn * 4 + 5];
  void pushup(int rt) {
    t[rt].mul = t[rt << 1].mul * t[rt << 1 | 1].mul;
    t[rt].sum = t[rt << 1].sum + t[rt << 1].mul * t[rt << 1 | 1].sum;
  }
  void build(int rt, int l, int r) {
    if (l == r) {
      t[rt].mul = t[rt].sum = T[l];
      return;
    }
    int mid = (l + r) >> 1;
    build(rt << 1, l, mid), build(rt << 1 | 1, mid + 1, r);
    pushup(rt);
  }
  void modify(int rt, int l, int r, int pos, double val) {
    if (l == r) {
      t[rt].mul = t[rt].sum = val;
      return;
    }
    int mid = (l + r) >> 1;
    if (pos <= mid)
      modify(rt << 1, l, mid, pos, val);
    else
      modify(rt << 1 | 1, mid + 1, r, pos, val);
    pushup(rt);
  }
  double __query(int rt, int l, int r, int ql, int qr) {
    if (ql <= l && r <= qr) return t[rt].mul;
    int mid = (l + r) >> 1;
    double ret = 1.0;
    if (ql <= mid) ret *= __query(rt << 1, l, mid, ql, qr);
    if (qr > mid) ret *= __query(rt << 1 | 1, mid + 1, r, ql, qr);
    return ret;
  }
  double query(int rt, int l, int r, int ql, int qr) {
    if (ql <= l && r <= qr) return t[rt].sum;
    int mid = (l + r) >> 1;
    double ret = 0;
    if (ql <= mid) ret += query(rt << 1, l, mid, ql, qr);
    if (qr > mid)
      ret += __query(rt << 1, l, mid, ql, mid) *
             query(rt << 1 | 1, mid + 1, r, ql, qr);
    return ret;
  }
};
SegmentTree tree;
int main() {
  int Q;
  scanf("%d %d", &N, &Q);
  for (int i = 1; i <= N; i++) {
    double a, b;
    scanf("%lf %lf", &a, &b);
    T[i] = (b - a) / a;
  }
  tree.build(1, 1, N);
  while (Q--) {
    int op;
    scanf("%d", &op);
    if (op == 1) {
      int pos;
      double a, b;
      scanf("%d %lf %lf", &pos, &a, &b);
      tree.modify(1, 1, N, pos, (b - a) / a);
    }
    if (op == 2) {
      int l, r;
      scanf("%d %d", &l, &r);
      printf("%.10f\n", 1 / (tree.query(1, 1, N, l, r) + 1.0));
    }
  }
  return 0;
}
