import math

N, H = map(int, input().split())
kiri = []
nage = []
for n in range(N):
    tmps = list(map(int, input().split()))
    kiri.append(tmps[0])
    nage.append(tmps[1])

kiri_max = max(kiri)
nage.sort(reverse=True)

count = 0
while (H > 0):
    if (len(nage) != 0):
        H -= nage[0]
        nage.pop(0)
        count += 1
    else:
        if ( H % kiri_max):
            count += H // kiri_max
        else:
            count += H // kiri_max + 1
        break

print(count)