#include <bits/stdc++.h>
template <typename T1, typename T2>
inline void chmin(T1 &a, T2 b) {
  if (a > b) a = b;
}
template <typename T1, typename T2>
inline void chmax(T1 &a, T2 b) {
  if (a < b) a = b;
}
const long kMax2 = 109;
const long kMax3 = 1009;
const long kMax4 = 10009;
const long kMax5 = 100009;
const long kMax6 = 1000009;
const long kInfI = 0x3F3F3F3F;
const float kInfF = 1e15;
const long long kMod = 1000000007;
const long long kMAX = 1000000000;
using namespace std;
using ll = long long;
inline int readInt() {
  char c = getchar();
  while (!isdigit(c) && c != '-') c = getchar();
  int sigma = 1;
  if (c == '-') {
    sigma = -1;
    c = getchar();
  }
  int x = 0;
  while (isdigit(c)) {
    x = x * 10 + c - '0';
    c = getchar();
  }
  return x * sigma;
}
template <class T>
void PrintVector(const vector<T> &v) {
  for (const auto &e : v) {
    cout << e << endl;
  }
}
template <class T>
void PrintVector(const vector<T> &v, int n) {
  for (long i = (0); i <= (n - 1); ++i) {
    cout << v[i] << endl;
  }
}
int main(int argc, char const *argv[]) {
  int n, h;
  int a_max = 0;
  int ans = 0;
  vector<int> a, b;
  cin >> n >> h;
  for (long i = (1); i <= (n); ++i) {
    int a0, b0;
    cin >> a0 >> b0;
    a.push_back(a0);
    b.push_back(b0);
    chmax(a_max, a0);
  }
  int h0 = 0;
  for (const auto &b0 : b) {
    if (b0 > a_max) {
      h0 += b0;
      ++ans;
      if (h0 >= h) break;
    }
  }
  if (h0 < h) {
    ans += (h - h0 + a_max - 1) / a_max;
  }
  cout << ans << endl;
  return 0;
}
