#include <bits/stdc++.h>
const int N = 100005;
int n, Qi;
double u[N];
namespace SE {
double A[N << 2], B[N << 2];
inline void Up(int t) {
  A[t] = A[t << 1] * A[t << 1 | 1];
  B[t] = B[t << 1] + A[t << 1] * B[t << 1 | 1];
}
void Build(int t, int l, int r) {
  if (l == r) return void(A[t] = B[t] = u[l]);
  int md = (l + r) >> 1;
  Build(t << 1, l, md);
  Build(t << 1 | 1, md + 1, r);
  Up(t);
}
void Modify(int t, int l, int r, int x) {
  if (l == r) return void(A[t] = B[t] = u[l]);
  int md = (l + r) >> 1;
  if (x <= md) Modify(t << 1, l, md, x);
  if (x > md) Modify(t << 1 | 1, md + 1, r, x);
  Up(t);
}
std::pair<double, double> Query(
    int t, int l, int r, int L, int R,
    std::pair<double, double> re = std::make_pair(1, 0)) {
  if (L <= l && r <= R) return std::make_pair(A[t], B[t]);
  int md = (l + r) >> 1;
  if (L <= md) {
    std::pair<double, double> r1 = Query(t << 1, l, md, L, R);
    re = std::make_pair(re.first * r1.first, re.second + re.first * r1.second);
  }
  if (md < R) {
    std::pair<double, double> r2 = Query(t << 1 | 1, md + 1, r, L, R);
    re = std::make_pair(re.first * r2.first, re.second + re.first * r2.second);
  }
  return re;
}
}  // namespace SE
int main() {
  scanf("%d%d", &n, &Qi);
  for (int i = 1, a, b; i <= n; ++i) {
    scanf("%d%d", &a, &b);
    double p = (double)a / b;
    u[i] = (1 - p) / p;
  }
  SE::Build(1, 1, n);
  for (int ty, a, b, x; Qi; --Qi) {
    scanf("%d", &ty);
    if (ty == 1) {
      scanf("%d%d%d", &x, &a, &b);
      double p = (double)a / b;
      u[x] = (1 - p) / p;
      SE::Modify(1, 1, n, x);
    } else {
      scanf("%d%d", &a, &b);
      std::pair<double, double> re = SE::Query(1, 1, n, a, b);
      printf("%.7f\n", 1 / (re.second + 1));
    }
  }
  return 0;
}
