from bisect import bisect_right,bisect_left
import sys
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)
B.sort()
ama=max(A)
x = bisect_right(B,ama)
ans = 0
if x ==N:
    if H%ama ==0:
        ans += H//ama 
    else:
        ans += H//ama +1
    print(ans)
    sys.exit()
for i in range(x,N):
    if H<=0:
        print(ans)
        sys.exit()
    elif H>0:
        H-=B[i]
        ans +=1
if H>0:
    if H%ama ==0:
        ans += H//ama 
    else:
        ans += H//ama +1
print(ans)