N,M = map(int,input().split())

X = [list(map(int,input().split())) for _ in range(N)]
X = sorted(X,key=lambda X:-X[0])
a = X[0][0]
X = sorted(X,key=lambda X:-X[1])

i = 0
count = 0
while M > 0:
	if i < N and X[i][1] > a:
		M -= X[i][1]
		i += 1
	else:
		count += -(-M//a)
		break
	count += 1

print(count)
