a = []
b = []
N,H = map(int,input().split())
for i in range(N):
    ca,cb = map(int,input().split())
    a.append(ca)
    b.append(cb)
count = 0
ma = max(a)
b.sort(reverse = True)
def ans():
    global N,H,count
    for i in range(N):
        if b[i] < ma:
            break
        H -= b[i]
        count += 1
        if H <= 0:
            return count
    count += H//ma
    return count
print(ans())
        