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(a)
    count = 0
    for i in range(N):
        if b[i]>A:
            count += 1
            H = H - b[i]
            if H <= 0:
                return count
    
    if H%A==0:
        return count + H//A
    else:
        return count + H//A + 1

if __name__ == "__main__":
    print(main())
