from math import ceil
n,h = map(int,input().split())
a = [0]*n
b = [0]*n
for i in range(n):
    a[i] , b[i] = map(int,input().split())
bs = list(sorted(b,reverse=True))
ma = max(a)
ret = 0
while ret < n:
    if bs[0] > ma:
        h -= bs[0]
        bs.pop(0)
        ret += 1
        if h < 0 : break
    else:
        break

if h > 0: ret += ceil(h/ma)
print(ret)
