#include <bits/stdc++.h>
using namespace std;
const int maxn = 100000 + 10;
struct TreeNode {
  int L, R;
  pair<double, double> val;
} tree[maxn << 2];
int a[maxn], b[maxn], n, q;
void pushUp(int root) {
  tree[root].val.first =
      tree[root << 1].val.first * tree[root << 1 | 1].val.first;
  tree[root].val.second =
      tree[root << 1].val.second +
      tree[root << 1].val.first * tree[root << 1 | 1].val.second;
}
void build(int L, int R, int root) {
  tree[root].L = L;
  tree[root].R = R;
  if (L == R) {
    return;
  }
  int mid = (L + R) >> 1;
  build(L, mid, root << 1);
  build(mid + 1, R, root << 1 | 1);
}
void update(int pos, pair<double, double> val, int root) {
  int L = tree[root].L, R = tree[root].R;
  if (L == R) {
    tree[root].val = val;
    return;
  }
  int mid = (L + R) >> 1;
  if (pos <= mid) {
    update(pos, val, root << 1);
  } else {
    update(pos, val, root << 1 | 1);
  }
  pushUp(root);
}
pair<double, double> query(int ql, int qr, int root) {
  int L = tree[root].L, R = tree[root].R;
  if (L >= ql && R <= qr) return tree[root].val;
  int mid = (L + R) >> 1;
  pair<double, double> a = make_pair(1.0, 0.0), b = make_pair(1.0, 0.0), c;
  if (ql <= mid) {
    a = query(ql, qr, root << 1);
  }
  if (qr > mid) {
    b = query(ql, qr, root << 1 | 1);
  }
  c.first = a.first * b.first;
  c.second = a.second + a.first * b.second;
  return c;
}
int main() {
  cin >> n >> q;
  build(1, n, 1);
  for (int i = 1; i <= n; i++) {
    double x, y;
    cin >> x >> y;
    double p = x / y;
    update(i, make_pair((1 - p) / p, (1 - p) / p), 1);
  }
  while (q--) {
    int type;
    cin >> type;
    if (type == 1) {
      int i, x, y;
      scanf("%d%d%d", &i, &x, &y);
      double p = double(x) / y;
      update(i, make_pair((1.0 - p) / p, (1.0 - p) / p), 1);
    } else {
      int l, r;
      scanf("%d%d", &l, &r);
      pair<double, double> t = query(l, r, 1);
      double p = t.second;
      if (p < 1e20)
        printf("%.6lf\n", 1.0 / (1 + p));
      else
        cout << "0.0000000" << endl;
    }
  }
  return 0;
}
