#include<bits/stdc++.h>
using namespace std;
void *wmem;
void sortF_L(int N, unsigned A[], void *mem = wmem){
  int bt, i, m, *sz;
  unsigned *arr, c;
  if(N < 256){
    sort(A, A+N);
    return;
  }
  bt = sizeof(unsigned) * 8;
  arr = (unsigned*)mem;
  sz = (int*)(arr+N);
  for(m=0;m<bt;m+=8){
    for(i=0;i<257;i++){
      sz[i] = 0;
    }
    for(i=0;i<N;i++){
      sz[ 1+((A[i]>>m)&255u) ]++;
    }
    for(i=1;i<257;i++){
      sz[i] += sz[i-1];
    }
    for(i=0;i<N;i++){
      c = ((A[i]>>m)&255u);
      arr[sz[c]++] = A[i];
    }
    swap(A, arr);
  }
}
void sortF_L(int N, int A[], void *mem = wmem){
  int *arr, i, x, y, z;
  unsigned *send;
  if(N < 256){
    sort(A, A+N);
    return;
  }
  send = (unsigned*)A;
  sortF_L(N, send, mem);
  if(A[0] < 0 || A[N-1] >= 0){
    return;
  }
  x = 0;
  y = N;
  while(x < y){
    z = (x+y) / 2;
    if(A[z] < 0){
      y = z;
    }
    else{
      x = z+1;
    }
  }
  arr = (int*)mem;
  z = 0;
  for(i=x;i<N;i++){
    arr[z++] = A[i];
  }
  for(i=0;i<x;i++){
    arr[z++] = A[i];
  }
  for(i=0;i<N;i++){
    A[i] = arr[i];
  }
}
void sortF_L(int N, unsigned long long A[], void *mem = wmem){
  int bt, i, m, *sz;
  unsigned c;
  unsigned long long *arr;
  if(N < 512){
    sort(A, A+N);
    return;
  }
  bt = sizeof(unsigned long long) * 8;
  arr = (unsigned long long*)mem;
  sz = (int*)(arr+N);
  for(m=0;m<bt;m+=8){
    for(i=0;i<257;i++){
      sz[i] = 0;
    }
    for(i=0;i<N;i++){
      sz[ 1+((A[i]>>m)&255u) ]++;
    }
    for(i=1;i<257;i++){
      sz[i] += sz[i-1];
    }
    for(i=0;i<N;i++){
      c = ((A[i]>>m)&255u);
      arr[sz[c]++] = A[i];
    }
    swap(A, arr);
  }
}
void sortF_L(int N, long long A[], void *mem = wmem){
  int i, x, y, z;
  long long *arr;
  unsigned long long *send;
  if(N < 512){
    sort(A, A+N);
    return;
  }
  send = (unsigned long long*)A;
  sortF_L(N, send, mem);
  if(A[0] < 0 || A[N-1] >= 0){
    return;
  }
  x = 0;
  y = N;
  while(x < y){
    z = (x+y) / 2;
    if(A[z] < 0){
      y = z;
    }
    else{
      x = z+1;
    }
  }
  arr = (long long*)mem;
  z = 0;
  for(i=x;i<N;i++){
    arr[z++] = A[i];
  }
  for(i=0;i<x;i++){
    arr[z++] = A[i];
  }
  for(i=0;i<N;i++){
    A[i] = arr[i];
  }
}
void rd(int &x){
  int k, m=0;
  x=0;
  for(;;){
    k = getchar_unlocked();
    if(k=='-'){
      m=1;
      break;
    }
    if('0'<=k&&k<='9'){
      x=k-'0';
      break;
    }
  }
  for(;;){
    k = getchar_unlocked();
    if(k<'0'||k>'9'){
      break;
    }
    x=x*10+k-'0';
  }
  if(m){
    x=-x;
  }
}
void wt_L(int x){
  char f[10];
  int m=0, s=0;
  if(x<0){
    m=1;
    x=-x;
  }
  while(x){
    f[s++]=x%10;
    x/=10;
  }
  if(!s){
    f[s++]=0;
  }
  if(m){
    putchar_unlocked('-');
  }
  while(s--){
    putchar_unlocked(f[s]+'0');
  }
}
template<class S, class T> inline S max_L(S a,T b){
  return a>=b?a:b;
}
template<class S, class T> inline S divup_L(S a, T b){
  return (a+b-1)/b;
}
template<class S, class T> inline S chmin(S &a, T b){
  if(a>b){
    a=b;
  }
  return a;
}
char memarr[96000000];
int A[100000], B[100000], H, N;
int main(){
  int i, mx, res;
  wmem = memarr;
  rd(N);
  rd(H);
  {
    int Lj4PdHRW;
    for(Lj4PdHRW=0;Lj4PdHRW<N;Lj4PdHRW++){
      rd(A[Lj4PdHRW]);
      rd(B[Lj4PdHRW]);
    }
  }
  {
    int KL2GvlyY, Q5VJL1cS;
    if(N==0){
      Q5VJL1cS = 0;
    }
    else{
      Q5VJL1cS = A[0];
      for(KL2GvlyY=1;KL2GvlyY<N;KL2GvlyY++){
        Q5VJL1cS = max_L(Q5VJL1cS, A[KL2GvlyY]);
      }
    }
    mx =Q5VJL1cS;
  }
  sortF_L(N,B);
  res =divup_L(H,mx);
  for(i=0;i<N;i++){
    H -= B[N-i-1];
    if(H <= 0){
      chmin(res, i+1);
      break;
    }
    chmin(res, i+1 + (divup_L(H,mx)));
  }
  wt_L(res);
  putchar_unlocked('\n');
  return 0;
}
// cLay varsion 20180208-1

// --- original code ---
// int N, H, A[100000], B[100000];
// {
//   int i, mx;
//   int res;
//   
//   rd(N,H,(A,B)(N));
//   mx = max(A(N));
//   sortF(N,B);
// 
//   res = H /+ mx;
//   rep(i,N){
//     H -= B[N-i-1];
//     if(H <= 0){
//       res <?= i+1;
//       break;
//     }
//     res <?= i+1 + (H /+ mx);
//   }
// 
//   wt(res);
// }


Measured memory_bytes: 1408