#!/usr/bin/env python3
import math
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())

b.sort()
m = max(a)
s = [0]
for i in range(N):
    b[i] = max(b[i], m)
    s.append(s[-1] + b[i])
    if s[-1] >= H:
        print(i + 1)
        break
else:
    print(max(N, math.ceil((H - sum(b)) / m) + N))
