def main():
    import sys
    input=sys.stdin.readline
    n,h=map(int,input().split())
    sword=[list(map(int,input().split())) for i in range(n)]
    m=max([sword[i][0] for i in range(n)])
    sword2=[sword[i][1] for i in range(n)]
    
    cnt=0
    for s in sword2:
        if m<s:
            cnt+=1
            h-=s
            if h<=0:
              print(cnt)
              exit()            
    cnt+=(h+m-1)//m
    print(cnt)
    
if __name__=='__main__':
    main()
