import sys
import math
input = sys.stdin.readline

def main():
    N, H = map(int, input().split())

    a = [0] * N
    b = [0] * N

    for i in range(N):
        t1, t2 = map(int, input().split())
        a[i] = t1
        b[i] = t2

    a = sorted(a, reverse=True)
    b = sorted(b, reverse=True)

    count = 0
    for i in range(N):
        if H > 0 and b[i] > a[0]:
            # print(H, "-", b[i], "=", H-b[i])
            H -= b[i]
            count += 1
        else:
            break
    # print(H, "-", math.ceil(H/a[0])*a[0], "=", H - math.ceil(H/a[0])*a[0])
    count += math.ceil(H/a[0])
    print(count)

if __name__ == "__main__":
    main()
