n,h = map(int,input().split())
ab = []
for _ in range(n):
    a, b = (int(x) for x in input().split())
    ab.append([a, b])
ab = sorted(ab, key=lambda x: -x[0])
x,y = ab.pop(0)
ab = sorted(ab, key=lambda x: -x[1])
count = 0
for i ,j in ab:
    if x <= j:
        h -= j
        count += 1
    else:
        break

if (h-y)%x==0:
    print(count+1+(h-y)//x)
else:
    print(count+2+(h-y)//x)