#include <bits/stdc++.h>
#include <boost/multiprecision/cpp_int.hpp>
using namespace std;

//#define int long long
//using ll = boost::multiprecision::cpp_int;
using ll = long long;
//constexpr int INF = 1e9;//INT_MAX=1<<31-1=2147483647
constexpr ll INF = (ll)1e18;//1<<63-1=9223372036854775807
constexpr ll MOD = (ll)1e9 + 7;
constexpr double EPS = 1e-9;
constexpr int dx[4]={1,0,-1,0};
constexpr int dy[4]={0,1,0,-1};
#ifdef LOCAL_ENV
	#define debug(var) std::cout<<#var" = "<<var<<std::endl
#else
	#define debug(var)
#endif
#define p(var) std::cout<<var<<std::endl
#define PI (acos(-1))
#define rep(i, n)   for(ll i=0, i##_length=(n); i< i##_length; ++i)
#define repeq(i, n) for(ll i=1, i##_length=(n); i<=i##_length; ++i)
#define all(a) (a).begin(), (a).end()
#define pb push_back
inline bool isnatural(double a) { return a>=0 && ceil(a)==floor(a); }
template<typename T> inline T power(T x, T n){ return n ? power(x*x%MOD,n/2)*(n%2?x:1)%MOD : 1; }
template<typename T> inline T gcd(T a, T b) { return b ? gcd(b,a%b) : a; }
template<typename T> inline T lcm(T a, T b) { return a / gcd(a,  b) * b; }
template<typename T1, typename T2>inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }
template<typename T1, typename T2>inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }
template<typename T1, typename T2> ostream& operator<<(ostream& s, const pair<T1, T2>& p) {return s << "(" << p.first << ", " << p.second << ")";}
template<typename T> ostream& operator<<(ostream& s, const vector<T>& v) {
	for (int i = 0, len = v.size(); i < len; ++i){
		s << v[i]; if (i < len - 1) s << "\t";
	}
	return s;
}
template<typename T> ostream& operator<<(ostream& s, const vector< vector<T> >& vv) {
	for (int i = 0, len = vv.size(); i < len; ++i){
		s << vv[i] << endl;
	}
	return s;
}
template<typename T1, typename T2> ostream& operator<<(ostream& s, const map<T1, T2>& m) {
	s << "{" << endl;
	for (typeof(m.begin()) itr = m.begin(); itr != m.end(); ++itr){
		s << "\t" << (*itr).first << " : " << (*itr).second << endl;
	}
	s << "}" << endl;
	return s;
}

/*-----8<-----8<-----*/

inline constexpr ll extgcd(ll a, ll b, ll &x, ll &y){ ll g = a; x = 1; y = 0; if(b){ g = extgcd(b, a % b, y, x); y -= a / b * x; } return g; }
inline constexpr ll invmod(ll a, ll m = MOD){ ll x = 0, y = 0; extgcd(a, m, x, y); return (x + m) % m; }
class Modint{
public:
	ll _num;
	constexpr Modint() : _num() { _num = 0; }
	constexpr Modint(ll x) : _num() { _num = x % MOD; if(_num < 0) _num += MOD; }
	inline constexpr Modint operator= (int x){ _num = x % MOD; if(_num<0) _num += MOD; return *this; }
	inline constexpr Modint operator= (ll x){ _num = x % MOD; if(_num<0) _num += MOD; return *this; }
	inline constexpr Modint operator= (Modint x){ _num = x._num; return *this; }
	inline constexpr Modint operator+ (int x){ return Modint(_num + x); }
	inline constexpr Modint operator+ (ll x){ return Modint(_num + x); }
	inline constexpr Modint operator+ (Modint x){ ll a = _num + x._num; if(a >= MOD) a -= MOD; return Modint{a}; }
	inline constexpr Modint operator+=(int x){ _num += x; _num %= MOD; if(_num < 0) _num += MOD; return *this; }
	inline constexpr Modint operator+=(ll x){ _num += x; _num %= MOD; if(_num < 0) _num += MOD; return *this; }
	inline constexpr Modint operator+=(Modint x){ _num += x._num; if(_num >= MOD) _num -= MOD; return *this; }
	inline constexpr Modint operator++(){ _num++; if(_num == MOD) _num = 0; return *this; }
	inline constexpr Modint operator- (int x){ return Modint(_num - x); }
	inline constexpr Modint operator- (ll x){ return Modint(_num - x); }
	inline constexpr Modint operator- (Modint x){ ll a = _num - x._num; if(a < 0) a += MOD; return Modint{a}; }
	inline constexpr Modint operator-=(int x){ _num -= x; _num %= MOD; if(_num < 0) _num += MOD; return *this; }
	inline constexpr Modint operator-=(ll x){ _num -= x; _num %= MOD; if(_num < 0) _num += MOD; return *this; }
	inline constexpr Modint operator-=(Modint x){ _num -= x._num; if(_num < 0) _num += MOD; return *this; }
	inline constexpr Modint operator--(){ _num--; if(_num == -1) _num = MOD - 1; return *this; }
	inline constexpr Modint operator* (int x){ return Modint(_num * (x % MOD)); }
	inline constexpr Modint operator* (ll x){ return Modint(_num * (x % MOD)); }
	inline constexpr Modint operator* (Modint x){ return Modint{_num * x._num % MOD}; }
	inline constexpr Modint operator*=(int x){ _num *= Modint(x); _num %= MOD; return *this; }
	inline constexpr Modint operator*=(ll x){ _num *= Modint(x); _num %= MOD; return *this; }
	inline constexpr Modint operator*=(Modint x){ _num *= x._num; _num %= MOD; return *this; }
	inline constexpr Modint operator/ (int x){ return Modint(_num * invmod(Modint(x), MOD)); }
	inline constexpr Modint operator/ (ll x){ return Modint(_num * invmod(Modint(x), MOD)); }
	inline constexpr Modint operator/ (Modint x){ return Modint{_num * invmod(x._num, MOD) % MOD}; }
	inline constexpr Modint operator/=(int x){ _num *= invmod(Modint(x), MOD); _num %= MOD; return *this; }
	inline constexpr Modint operator/=(ll x){ _num *= invmod(Modint(x), MOD); _num %= MOD; return *this; }
	inline constexpr Modint operator/=(Modint x){ _num *= invmod(x._num, MOD); _num %= MOD; return *this; }
	inline constexpr Modint pow(ll x){ ll i = 1; Modint ans = 1, cnt = *this; while(i <= x){ if(x & i){ ans *= cnt; x ^= i; } cnt *= cnt; i *= 2; } return ans; }
	inline constexpr operator ll() const { return _num; }
};
vector<Modint> fac(1, 1), inv(1, 1);
inline void reserve(size_t a){
	if(fac.size() >= a) return;
	if(a < fac.size() * 2) a = fac.size() * 2;
	if(a >= MOD) a = MOD;
	while(fac.size() < a) fac.push_back(fac.back() * ll(fac.size()));
	inv.resize(fac.size());
	inv.back() = Modint(1) / fac.back();
	for(ll i = inv.size() - 1; !inv[i - 1]; i--) inv[i - 1] = inv[i] * i;
}
inline Modint factorial(ll n){ if(n < 0) return 0; reserve(n + 1); return fac[n]; }
inline Modint nPk(ll n, ll k){ if(k < 0 || n < k) return 0; reserve(n + 1); return fac[n] * inv[n - k]; }
inline Modint nCk(ll n, ll k){ if(k < 0 || n < k) return 0; reserve(n + 1); return fac[n] * inv[k] * inv[n - k]; }
inline Modint nHk(ll n, ll k){ return nCk(n + k - 1, k); } // k個をn部屋に分ける


inline static void upflag(int *flags,int BITS,int i) {
	flags[i / BITS] |= 1 << (i % BITS);
}

inline static int getflag(int *flags,int BITS,int i) {
	return (flags[i / BITS] >> (i % BITS)) & 1;
}

//MAXVAL以下の素数を詰めたvectorを返す
vector<int> eratosthenes(int MAXVAL){
	int BITS = (sizeof(int) * 8);
	int FLAGS_NUM = (MAXVAL / BITS + 1);
	int flags[FLAGS_NUM] = {};
	int i, j, f, s;
	int max = (int)sqrt(MAXVAL) + 1;
	vector<int> primelist;
	primelist.push_back(2);
	primelist.push_back(3);
	for (i = 5, f = 4; i <= max; i += (f = 6 - f)) {
		if (!getflag(flags,BITS,i)) {
			primelist.push_back(i);
			s = MAXVAL / i;
			for (j = s - !(s & 1); j >= i; j -= 2) {
				if (!getflag(flags,BITS,i))
					upflag(flags,BITS,i*j);
			}
		}
	}
	for (; i <= MAXVAL; i += (f = 6 - f)){
		if (!getflag(flags,BITS,i)){
			primelist.push_back(i);
		}
	}
	return primelist;
}

////

signed main() {
	ll N,H;
	cin >> N>>H;
	vector<pair<ll,ll>> a(N);
	rep(i,N){
		cin>>a[i].first>>a[i].second;
	}

	auto maxit=max_element(a.begin(), a.end(), [](const pair<ll,ll> &x, const pair<ll,ll> &y) {
        return x.first < y.first;
    });
	ll amax=maxit->first;

	sort(a.begin(), a.end(), [](const pair<ll,ll> &x, const pair<ll,ll> &y) {
		return x.second < y.second;
	});
	debug(a);
	auto it = lower_bound(a.begin(), a.end(), pair<ll,ll>(0,amax), [](const pair<ll,ll> &x, const pair<ll,ll>& y) {
		 return x.second < y.second;
	});
	ll sum=accumulate(it, a.end(), 0LL, [](ll acc, pair<ll,ll> &i) {
    	return acc + i.second;
	});

	ll ans=0;
	if(sum>H){
		ll t=0;
		ll i=N-1;
		while(1){
			ans++;
			t+=a[i].second;
			if(t>=H)break;
			i--;
		}
	}else{
		ll amari=H-sum;
		ans=N-(it-a.begin());
		ans+=(amari+amax-1)/amax;
		debug(N-(it-a.begin()));
		debug(amax);
		debug(sum);
	}
	p(ans);
	return 0;
}



Measured memory_bytes: 1792