from math import ceil

def main():
    n,h = map(int,input().split())
    a = [0 for _ in range(n)]
    b = [0 for _ in range(n)]
    for i in range(n):
        a[i],b[i] = map(int,input().split())

    a_max = max(a)
    ans = 0

    for i in range(n):
        if b[i]>=a_max:
            h -= b[i]
            ans += 1
        
        if h<=0:
            print(ans)
            exit()
    ans += ceil(h/a_max)
    print(int(ans))




if __name__ == "__main__":
    main()