# ABC085D - Katana Thrower
import sys
input = sys.stdin.readline

def main():
    N, H = tuple(map(int, input().split()))
    AB = tuple(tuple(map(int, input().split())) for _ in range(N))
    A, B = zip(*AB)
    C = sorted([(i, 0) for i in A] + [(i, 1) for i in B], reverse=1)
    ans = 0
    for i, t in C:
        if t == 0:
            ans += (H + i - 1) // i
            break
        else:
            ans += 1
            H -= i
    print(ans)


if __name__ == "__main__":
    main()