#include <bits/stdc++.h>
using namespace std;
const int MAX = 1e5 + 7;
int n, q;
double a[MAX], b[MAX];
const int N = 2;
typedef struct node {
  double a[2][2];
} node;
node tree[4 * MAX];
node I;
node mul(double a[N][N], double b[N][N]) {
  node d;
  for (int i = 0; i < N; i++)
    for (int j = 0; j < N; j++) d.a[i][j] = 0;
  for (int i = 0; i < N; i++)
    for (int j = 0; j < N; j++)
      for (int k = 0; k < N; k++) d.a[i][j] = (d.a[i][j] + a[i][k] * b[k][j]);
  double mx = 0;
  for (int i = 0; i < 2; i++)
    for (int j = 0; j < 2; j++) mx = max(mx, abs(d.a[i][j]));
  if (mx > 1e9) {
    for (int i = 0; i < 2; i++)
      for (int j = 0; j < 2; j++) d.a[i][j] = d.a[i][j] / mx;
  }
  return d;
}
void maketree(int beg, int last, int si) {
  if (beg == last) {
    tree[si].a[0][0] = 1;
    tree[si].a[1][0] = 1;
    tree[si].a[0][1] = 0;
    tree[si].a[1][1] = b[beg] / a[beg] - 1;
    return;
  }
  maketree(beg, (beg + last) / 2, 2 * si + 1);
  maketree((beg + last) / 2 + 1, last, 2 * si + 2);
  tree[si] = mul(tree[2 * si + 1].a, tree[2 * si + 2].a);
}
void update(int beg, int last, int p, int q, int si) {
  if (beg > q || last < p) return;
  if (beg == last) {
    tree[si].a[1][1] = b[beg] / a[beg] - 1;
    return;
  }
  update(beg, (beg + last) / 2, p, q, 2 * si + 1);
  update((beg + last) / 2 + 1, last, p, q, 2 * si + 2);
  tree[si] = mul(tree[2 * si + 1].a, tree[2 * si + 2].a);
}
node query(int beg, int last, int p, int q, int si) {
  if (beg > q || last < p) return I;
  if (p <= beg && q >= last) return tree[si];
  return mul(query(beg, (beg + last) / 2, p, q, 2 * si + 1).a,
             query((beg + last) / 2 + 1, last, p, q, 2 * si + 2).a);
}
int main() {
  ios_base::sync_with_stdio(false);
  cout << fixed;
  cout.precision(10);
  I.a[0][0] = I.a[1][1] = 1;
  I.a[1][0] = I.a[0][1] = 0;
  cin >> n >> q;
  for (int i = 0; i < n; i++) cin >> a[i] >> b[i];
  maketree(0, n - 1, 0);
  while (q--) {
    int t;
    cin >> t;
    if (t == 1) {
      int i, a, b;
      cin >> i >> a >> b;
      i--;
      ::a[i] = a;
      ::b[i] = b;
      update(0, n - 1, i, i, 0);
    } else {
      int l, r;
      cin >> l >> r;
      node temp = query(0, n - 1, l - 1, r - 2, 0);
      double num = temp.a[0][0] * a[r - 1] + temp.a[0][1] * b[r - 1];
      double den = temp.a[1][0] * a[r - 1] + temp.a[1][1] * b[r - 1];
      cout << num / den << endl;
    }
  }
  return 0;
}
