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)]
    mainweapon=max([sword[i][0] for i in range(n)])
    sword2=[sword[i][1] for i in range(n)]
    
    cnt=0
    for i in range(n):
        if mainweapon<sword2[i]:
            cnt+=1
            h-=sword2[i]
            if h<0:
              print(cnt)
              exit()            
    cnt+=(h+mainweapon-1)//mainweapon
    print(cnt)
    
if __name__=='__main__':
    main()
