#include <bits/stdc++.h>
using namespace std;
const int P = 1e9 + 7;
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
long long qpow(long long a, long long n) {
  long long r = 1 % P;
  for (a %= P; n; a = a * a % P, n >>= 1)
    if (n & 1) r = r * a % P;
  return r;
}
void exgcd(long long a, long long b, long long &d, long long &first,
           long long &second) {
  b                          ? exgcd(b, a % b, d, second, first),
      second -= a / b *first : first = 1, second = 0, d = a;
}
long long inv(long long first) {
  return first <= 1 ? 1 : inv(P % first) * (P - P / first) % P;
}
const int N = 1e5 + 10;
int n, m;
struct _ {
  double L, R;
  _() {}
  _(int first, int second) { L = R = (double)first / second; }
  _(double l, double r) : L(l), R(r) {}
  _ operator+(const _ &rhs) const {
    return _(L * rhs.L / (1 - (1 - rhs.L) * R),
             rhs.R + (1 - rhs.R) * R * rhs.L / (1 - (1 - rhs.L) * R));
  }
} v[N << 2];
void build(int o, int l, int r) {
  if (l == r) {
    int first, second;
    scanf("%d%d", &first, &second);
    v[o] = _(first, second);
    return;
  }
  build((o << 1), l, ((l + r) >> 1)),
      build(((o << 1) | 1), ((l + r) >> 1) + 1, r),
      v[o] = v[(o << 1)] + v[((o << 1) | 1)];
}
void upd(int o, int l, int r, int pos, int first, int second) {
  if (l == r) return v[o] = _(first, second), void();
  if (((l + r) >> 1) >= pos)
    upd((o << 1), l, ((l + r) >> 1), pos, first, second);
  else
    upd(((o << 1) | 1), ((l + r) >> 1) + 1, r, pos, first, second);
  v[o] = v[(o << 1)] + v[((o << 1) | 1)];
}
_ qry(int o, int l, int r, int ql, int qr) {
  if (ql <= l && r <= qr) return v[o];
  if (((l + r) >> 1) < ql)
    return qry(((o << 1) | 1), ((l + r) >> 1) + 1, r, ql, qr);
  if (((l + r) >> 1) >= qr) return qry((o << 1), l, ((l + r) >> 1), ql, qr);
  return qry((o << 1), l, ((l + r) >> 1), ql, qr) +
         qry(((o << 1) | 1), ((l + r) >> 1) + 1, r, ql, qr);
}
int main() {
  scanf("%d%d", &n, &m);
  build(1, 1, n);
  for (int i = 1; i <= m; ++i) {
    int op, pos, a, b;
    scanf("%d", &op);
    if (op == 1) {
      scanf("%d%d%d", &pos, &a, &b);
      upd(1, 1, n, pos, a, b);
    } else {
      scanf("%d%d", &a, &b);
      printf("%.12lf\n", qry(1, 1, n, a, b).L);
    }
  }
}
