import sys
import math
input = sys.stdin.readline

def main():
    N, H = map(int, input().split())
    b = [0] * N
    a_max = 0
    for i in range(N):
        t1, t2 = map(int, input().split())
        a_max = max(a_max, t1)
        b[i] = t2

    b = sorted(b, reverse=True)

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

if __name__ == "__main__":
    main()
