#include <bits/stdc++.h>
using namespace std;
const long long inf = 1e18;
inline long long f(pair<long long, long long> coeff, long long x) {
  if ((long double)coeff.first * x + coeff.second < -inf) return -inf;
  return coeff.first * x + coeff.second;
}
inline bool check(pair<long long, long long> a, pair<long long, long long> b,
                  pair<long long, long long> c) {
  double u = double(b.second - a.second) / (a.first - b.first);
  double v = double(b.second - c.second) / (c.first - b.first);
  return u <= v;
}
struct Hull {
  vector<pair<long long, long long>> q;
  void add(long long k, long long b) {
    if (!q.empty() && q.back().first == k) {
      b = min(b, q.back().second);
      q.pop_back();
    }
    while (q.size() > 1 && !check(q[q.size() - 2], q.back(), {k, b}))
      q.pop_back();
    q.emplace_back(k, b);
  }
  long long query(long long x) {
    if (q.empty()) return inf;
    int lo = 0, hi = q.size() - 1;
    while (lo < hi) {
      int mi = lo + hi >> 1;
      if (f(q[mi], x) > f(q[mi + 1], x))
        lo = mi + 1;
      else
        hi = mi;
    }
    return f(q[lo], x);
  }
} hull;
int n;
long long s, now;
long long get(long long tar, long long LIMIT = s) {
  long long lo = now, hi = LIMIT;
  while (lo < hi) {
    long long mi = lo + hi >> 1;
    if (hull.query(mi) <= tar)
      hi = mi;
    else
      lo = mi + 1;
  }
  return lo;
}
int main() {
  scanf("%d%lld", &n, &s);
  map<int, int> lines;
  for (int(i) = (1); (i) <= (n); (i)++) {
    int v, c;
    scanf("%d%d", &v, &c);
    lines[c] = max(lines[c], v);
  }
  hull.add(-lines.begin()->second, 0);
  int mx = lines.begin()->second;
  for (auto it : lines)
    if (it.second > mx) {
      if (it.first >= s) break;
      long long x = get(-it.first, it.first), y = hull.query(x);
      hull.add(-it.second, y + it.first + it.second * x);
      mx = it.second;
      now = x;
    }
  printf("%lld", get(-s));
}
