n,h=map(int,input().split())
X=[]
for i in range(n):
    a,b=map(int,input().split())
    X.append([a,b])
    
X.sort(key=lambda x:x[0],reverse=True)

cnt=0

for i in range(1,n):
    if X[i][1]>=X[0][0]:
        h-=X[i][1]
        cnt+=1
        if h<=0:
            break

if h>0:
    cnt+=h//X[0][0]
    
print(cnt)