#include <bits/stdc++.h>
                                        #include<iostream>
                                        #include<cstdio>
                                        #include<vector>
                                        #include<queue>
                                        #include<map>
                                        #include<cstring>
                                        #include<string>
                                        #include <math.h>
                                        #include<algorithm>
                                    //    #include <boost/multiprecision/cpp_int.hpp>
                                        #include<functional>
                                #define int long long
                                        #define inf  1000000007
                                        #define pa pair<int,int>
                                        #define ll long long
                                        #define pal pair<double,pa>
                                        #define ppa pair<int,int>
                                        #define ppap pair<int,pa>
                                        #define ssa pair<string,int>
                                        #define  mp make_pair
                                        #define  pb push_back
                                        #define EPS (1e-10)
                                        #define equals(a,b) (fabs((a)-(b))<EPS)
                                  #define VI vector<int>
                                        using namespace std;
                                        
                                  class pas{
                                    	public:
                                    	int x,y;
                                    	pas(int x=0,int y=0):x(x),y(y) {}
                                    	pas operator + (pas p) {return pas(x+p.x,y+p.y);}
                                    	pas operator - (pas p) {return pas(x-p.x,y-p.y);}
                                    	pas operator * (int a) {return pas(x*a,y*a);}
                                    	pas operator / (int a) {return pas(x/a,y/a);}
                                    //	double absv() {return sqrt(norm());}
                                    	int norm() {return x*x+y*y;}
                                    	bool operator < (const pas &p) const{
                                    		return x != p.x ? x<p.x: y<p.y;
                                    	}
                                    	bool operator == (const pas &p) const{
                                    		return x==p.x && y==p.y;
                                    	}
                                    };

int n,h;
int a[100030],b[100030];
           signed main(){
   	//	int pr[3];
     cin>>n>>h;
           	int am=0;
           	for(int i=0;i<n;i++)cin>>a[i]>>b[i];
           	 	for(int i=0;i<n;i++)am=max(am,a[i]);
           	
           	sort(b,b+n);
           	
           	int ans=inf+inf/10;
           	int kazu=0;
           	int su=0;
           	for(int i=n-1;i>=0;i--){
           	su+=b[i];
           		kazu++;
           		
           		if(h<=su) ans=min(ans,kazu);
           		else ans=min(ans,kazu+(h-su)/am+!!((h-su)%am));
           	}
      
           	
           	cout<<ans<<endl;
           }
             

Measured memory_bytes: 1792