import java.util.*;
import java.io.*;

public class Main{
    public static void main(String[] args){
        FastScanner fsc=new FastScanner();
        int n=fsc.nextInt();
        long h=fsc.nextLong();
        long[][] dam=new long[n][2];
        long repDamage=0;;
        for(int i=0;i<n;i++){
            dam[i][0]=fsc.nextLong();
            dam[i][1]=fsc.nextLong();
            repDamage=Math.max(repDamage,dam[i][0]);
        }
        fsc.close();
        Arrays.sort(dam,new C());
        long sumDam=0;
        long ans=0;
        for(long[] sword:dam){
            if(sword[1]>repDamage){
                sumDam+=sword[1];
                ans++;
                if(sumDam>=h){
                    System.out.println(ans);
                    return;
                }
            }
        }
        long rest=h-sumDam;
        while(rest>0){
            rest-=repDamage;
            ans++;
        }
        System.out.println(ans);
    }

    static class C implements Comparator<long[]>{
        @Override
        public int compare(long[] o1, long[] o2){
            return o1[1]<o2[1]?1:o1[1]>o2[1]?-1:0;
        }
    }

    static class FastScanner {
        private final InputStream in = System.in;
        private final byte[] buffer = new byte[1024];
        private int ptr = 0;
        private int buflen = 0;
        private boolean hasNextByte() {
            if (ptr < buflen) {
                return true;
            }else{
                ptr = 0;
                try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            }
            return true;
        }
        private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
        private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
        public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
        public String next() {
            if (!hasNext()) throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while(isPrintableChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }
        public long nextLong() {
            if (!hasNext()) throw new NoSuchElementException();
            long n = 0;
            boolean minus = false;
            int b = readByte();
            if (b == '-') {
                minus = true;
                b = readByte();
            }
            if (b < '0' || '9' < b) {
                throw new NumberFormatException();
            }
            while(true){
                if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                }else if(b == -1 || !isPrintableChar(b)){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                }
                b = readByte();
            }
        }
        public int nextInt() {
            long nl = nextLong();
            if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
            return (int) nl;
        }
        public double nextDouble() { return Double.parseDouble(next());}
        public void close(){
            try{in.close();}
            catch(IOException e){e.printStackTrace();}
        }
    }
}

Measured memory_bytes: 27600