n,h = map(int,input().split())
a = [[0]*2 for i in range(n)]

for i in range(n):
    a_,b_ = map(int,input().split())
    a[i][0] = a_
    a[i][1] = b_
a.sort(key=lambda x: x[0],reverse = True)
b = a[0][0]
c = a[0][1]
a.pop(0)
a.sort(key=lambda x: x[1],reverse = True)
ans =0
count = 0
check = True
if h <= c:
    ans = 1
else:
    for i in range(len(a)):
        if a[i][1] < b:
            break
        else:
            count += a[i][1]
            ans +=1
            if count >= h:
                check = False
                break
    if check:
         d = h - count - c
         ans +=1
         if d > 0:
             e = d // b
             ans +=e
             if d % b != 0:
                 ans += 1
print(ans)