NH = input().split()
N = int(NH[0])
H = int(NH[1])
a = []
b = []
for v in range(N):
    L = input().split()
    a.append(L[0])
    b.append(L[1])
a = list(map(int, a))
b = list(map(int, b))
a.sort(reverse = True)
b.sort(reverse = True)
c = 0
count = 0
while c < H:
    if len(b) > 0 and a[0] < b[0]:
        c = c + b.pop(0)
        count = count + 1 
    else:
        break
if c < H:
    count = count -(-((H - c)//a[0]))
print(count)