#include <bits/stdc++.h>
using namespace std;
int N, Q;
const int NMax = 100005;
const double lim = 1000000000.0;
long double Sum[NMax * 4], Prod[NMax * 4], P[NMax * 4];
long double sum, prod;
void Read() {
  scanf("%d%d", &N, &Q);
  for (int i = 1; i <= N; i++) {
    int a, b;
    scanf("%d%d", &a, &b);
    P[i] = (long double)a / (long double)b;
  }
}
void buildTree(int K, int L, int R) {
  if (L == R) {
    Sum[K] = (1.0 - P[L]) / P[L];
    Prod[K] = Sum[K];
    return;
  }
  buildTree(K * 2, L, (L + R) / 2);
  buildTree(K * 2 + 1, (L + R) / 2 + 1, R);
  Sum[K] = Sum[K * 2] + Prod[K * 2] * Sum[K * 2 + 1];
  Prod[K] = Prod[K * 2] * Prod[K * 2 + 1];
}
void Update(int K, int L, int R, int pos) {
  if (L == R) {
    Sum[K] = (1.0 - P[L]) / P[L];
    Prod[K] = Sum[K];
    return;
  }
  if (pos > (L + R) / 2)
    Update(K * 2 + 1, (L + R) / 2 + 1, R, pos);
  else
    Update(K * 2, L, (L + R) / 2, pos);
  Sum[K] = Sum[K * 2] + Prod[K * 2] * Sum[K * 2 + 1];
  Prod[K] = Prod[K * 2] * Prod[K * 2 + 1];
}
void Query(int K, int L, int R, int x, int y) {
  if (L > R || L > y || R < x) return;
  if (L >= x && R <= y) {
    sum += Sum[K] * prod;
    prod *= Prod[K];
    return;
  }
  Query(K * 2, L, (L + R) / 2, x, y);
  Query(K * 2 + 1, (L + R) / 2 + 1, R, x, y);
}
void Solve() {
  for (int i = 1; i <= Q; i++) {
    int type, pos, a, b;
    scanf("%d", &type);
    if (type == 1) {
      scanf("%d%d%d", &pos, &a, &b);
      P[pos] = (long double)a / (long double)b;
      Update(1, 1, N, pos);
    } else {
      scanf("%d%d", &a, &b);
      sum = 0.0;
      prod = 1.0;
      Query(1, 1, N, a, b);
      if (isnan(sum) || isinf(sum)) {
        cout << "0.0\n";
      } else
        cout << fixed << setprecision(15) << (1.0 / (sum + 1.0)) << "\n";
    }
  }
}
int main() {
  Read();
  buildTree(1, 1, N);
  Solve();
  return 0;
}
