if __name__ == "__main__":
    N, H = map(int, input().split())
    ab = []
    for i in range(N):
        a,b = map(int, input().split())
        ab.append([b, -a])
    ab.sort()
    ab = list(reversed(ab))
    res = 0
    result = 2 ** 100
    for b,a in ab:
        a *= -1
        H -= b
        res += 1
        if H <= 0:
            result = min(result, res)
            break
        tmp = res + H // a
        if H % a != 0:
            tmp += 1
        result = min(result, tmp)
            
    print (result)
        
    