def main():
    from sys import stdin
    input = lambda :stdin.readline().rstrip()
    N,H = map(int,input().split())
    A = []
    B = []
    for i in range(N):
        a,b = map(int,input().split())
        A.append(a)
        B.append(b)
    A.sort()
    B.sort() #
    a = A.pop()
    b = B.pop()
    ans = 0
    from math import ceil
    while H > 0:
        if b > a:
            ans += 1
            H -= b
            if B:
                b = B.pop()
            continue
            
        
        ans += ceil(H/a)
        print(ans)
        return



main()
        

        