#include <cstdio>
#include <cstring>
#include <cstdint>
#include <cstdlib>
#include <cstddef>

#include <vector>
#include <algorithm>
#include <type_traits>

namespace FastIn {
  static constexpr size_t BUF_SIZE=1<<17, INT_LEN=24, FLT_LEN=400;
  static char buf[BUF_SIZE|1]={}, *pos=buf, *endbuf=nullptr;

  inline bool rebuffer() {
    size_t rest=endbuf-pos;
    if (static_cast<ptrdiff_t>(rest) > pos-buf) {
      // not disjoint
      return true;
    }

    std::memcpy(buf, pos, rest);
    pos = buf;
    size_t len=std::fread(pos+rest, 1, BUF_SIZE-rest, stdin);
    *(endbuf = buf + (rest+len)) = 0;

    return *pos;
  }

  inline bool scan(char &in) {
    if ((in = *pos)) {
      ++pos;
      return true;
    }

    return rebuffer() && (in = *pos++);
  }

  inline bool scan(char *in) {
    if ((*in = *pos) == 0) {
      if (rebuffer() && (*in = *pos) == 0) {
        return false;
      }
    }
    ++in;
    while (true) {
      if ((*in = *pos++) == 0) {
        if (rebuffer() && (*in = *pos++) == 0) {
          return true;
        }
      }
      ++in;
    }
  }

  inline bool scan(double &in) {
    if (pos + FLT_LEN >= endbuf && !rebuffer()) {
      in = 0.0;
      return false;
    }

    char *tmp;
    in = std::strtod(pos, &tmp);
    pos = tmp;
    return true;
  }

  template <class Int>
  inline bool scan(
      Int &in,
      typename std::enable_if<std::is_signed<Int>::value>::type *un=nullptr
  ) {
    in = 0;

    // assume that no redundant whitespace appears
    if (pos + INT_LEN >= endbuf && !rebuffer()) {
      return false;
    }

    // assume that ' ' < '+' < '-' < '0' < '9'
    while (*pos < '-') {
      ++pos;
    }

    bool neg=false;
    if (*pos == '-') {
      ++pos;
      neg = true;
    }

    // assume that numbers are separated by the character whose value is
    // less than '0' (e.g. whitespaces, newlines)
    do {
      in = in*10 + (*pos)-'0';
    } while (*++pos >= '0');

    if (neg) {
      in = -in;
    }

    ++pos;
    return true;
  }

  template <class Int>
  inline bool scan(
      Int &in,
      typename std::enable_if<!std::is_signed<Int>::value>::type *un=nullptr
  ) {
    in = 0;

    // assume that no redundant whitespace appears
    if (pos + INT_LEN >= endbuf && !rebuffer()) {
      return false;
    }

    // assume that ' ' < '0' < '9' and minus signs do not appear
    //while (*pos < '0') {
    //  ++pos;
    //}

    // assume that numbers are separated by the character whose value is
    // less than '0' (e.g. whitespaces, newlines)
    do {
      in = in*10 + (*pos)-'0';
    } while (*++pos >= '0');

    ++pos;
    return true;
  }

  inline bool eat() {
    if (*pos > ' ') {
      return true;
    }

    do {
      if (*pos == 0 && !rebuffer()) {
        return false;
      }
    } while (*++pos <= ' ');

    return true;
  }

  inline bool eat(char ch) {
    if (*pos == ch) {
      return true;
    }

    do {
      if (*pos == 0 && !rebuffer()) {
        return false;
      }
    } while (*++pos != ch);

    return true;
  }

  class Scanner {
    bool rebuffer() {
      return FastIn::rebuffer();
    }

  public:
    Scanner() {
      endbuf = pos + std::fread(buf, 1, BUF_SIZE, stdin);
    }

    template <class T>
    inline bool scan(T &in) {
      return FastIn::scan(in);
    }

    template <class First, class... Rest>
    inline bool scan(First &in, Rest &...ins) {
      return scan(in) && scan(ins...);
    }
  };
}

namespace FastOut {
  static constexpr size_t BUF_SIZE=1<<17, INT_LEN=24, FLT_LEN=400;
  static constexpr char FLT_FMT[]="%.16f";
  static char buf[BUF_SIZE|1]={}, *pos=buf, *endbuf=pos+BUF_SIZE;
  inline void flush() {
    std::fwrite(buf, 1, pos-buf, stdout);
    pos = buf;
  }

  inline void print(const char out) {
    if (pos == endbuf) {
      flush();
    }
    *pos++ = out;
  }

  inline void print(const char *out) {
    size_t len=std::strlen(out);
    if (pos + len >= endbuf) {
      flush();
      if (len >= BUF_SIZE) {
        std::fwrite(out, 1, len, stdout);
        return;
      }
    }
    std::memcpy(pos, out, len);
    pos += len;
  }

  template <class Char, size_t Len>
  inline void print(const Char (&out)[Len]) {
    print(&out[0]);
  }

  inline void print(const double out) {
    char minibuf[FLT_LEN];
    size_t len=std::snprintf(minibuf, FLT_LEN, FLT_FMT, out);
    if (pos + len >= endbuf) {
      flush();
    }
    std::memcpy(pos, minibuf, len);
    pos += len;
  }

  template <class Int>
  inline void print(
      Int out,
      typename std::enable_if<std::is_signed<Int>::value>::type *un=nullptr
  ) {
    if (out == 0) {
      if (pos == endbuf) {
        flush();
      }
      *pos++ = '0';
      return;
    }

    if (out < 0) {
      if (pos == endbuf) {
        flush();
      }
      *pos++ = '-';
    }

    char minibuf[INT_LEN], *minipos=minibuf+INT_LEN;
    while (out > 0) {
      *--minipos = '0' + out%10;
      out /= 10;
    }
    size_t len=(minibuf+INT_LEN)-minipos;
    if (pos + len >= endbuf) {
      flush();
    }
    std::memcpy(pos, minipos, len);
    pos += len;
  }

  template <class Int>
  inline void print(
      Int out,
      typename std::enable_if<!std::is_signed<Int>::value>::type *un=nullptr
  ) {
    if (out == 0) {
      if (pos == endbuf) {
        flush();
      }
      *pos++ = '0';
      return;
    }

    char minibuf[INT_LEN], *minipos=minibuf+INT_LEN;
    while (out > 0) {
      *--minipos = '0' + out%10;
      out /= 10;
    }
    size_t len=(minibuf+INT_LEN)-minipos;
    if (pos + len >= minibuf) {
      flush();
    }
    std::memcpy(pos, minipos, len);
    pos += len;
  }

  template <class First, class... Rest>
  inline void print(const First &out, const Rest &...outs) {
    print(out);
    print(outs...);
  }

  class Printer {
    inline void flush() {
      FastOut::flush();
    }

  public:
    ~Printer() {
      flush();
    }

    template <class T>
    inline void print(const T out) {
      FastOut::print(out);
    }

    template <class First, class... Rest>
    inline void print(const First &&out, const Rest &&...outs) {
      print(out);
      print(outs...);
    }

    template <class T>
    inline void println(const T out) {
      print(out);
      print('\n');
    }
  };
}

template <class RandomIt>
void rsort(RandomIt first, RandomIt last) {
  using IntType = typename RandomIt::value_type;
  intmax_t cur_shift=0, max_exp=sizeof(IntType);
  std::vector<IntType> work(last-first);
  for (int i=0; i<max_exp; ++i) {
    size_t num[256]={};

    for (RandomIt it=first; it<last; ++it)
      ++num[((*it)>>cur_shift)&255];

    {
      size_t tmp=0;
      for (int j=0; j<256; ++j)
        std::swap(tmp, num[j]+=tmp);
    }

    for (RandomIt it=first; it<last; ++it)
      work[num[((*it)>>cur_shift)&255]++] = *it;

    {
      size_t j=0;
      for (RandomIt it=first; it<last; ++it)
        *it = work[j++];
    }

    cur_shift += 8;
  }

  if (!std::is_signed<IntType>::value) return;

  RandomIt mid=last;
  for (RandomIt it=last; --it>=first;)
    if (*it >= 0) {
      mid = ++it;
      break;
    }

  if (mid == last)
    return;

  std::copy(first, mid, work.begin()+(last-mid));
  std::copy(mid, last, work.begin());
  std::copy(work.begin(), work.end(), first);
}

FastIn::Scanner cin;
FastOut::Printer cout;

int main() {
  unsigned N;
  int H;
  cin.scan(N);
  cin.scan(H);

  unsigned a=0;
  std::vector<unsigned> b(N);
  for (unsigned i=0; i<N; ++i) {
    unsigned aa;
    cin.scan(aa, b[i]);
    if (a < aa)
      a = aa;
  }

  rsort(b.begin(), b.end());
  int res=0;
  for (size_t i=b.size(); i--;) {
    if (b[i] <= a) break;
    H -= b[i];
    ++res;
    if (H <= 0) {
      cout.println(res);
      return 0;
    }
  }

  cout.println(res+(H+a-1)/a);
}


Measured memory_bytes: 1152