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
for i in range(len(a)):
    count += a[i][1]
    ans +=1
    if count >= h:
        check = False
        break
if check:
     d = h - count - c
     ans +=1
     e = d // b
     ans +=e
     if d % b != 0:
         ans += 1
print(ans)