n,k=map(int,input().split())
choc=[]
for i in range(n):
    choc.append(list(map(int,input().split())))
maxs=0
for i in range(len(choc)):
    maxs=max(maxs,max(choc[i]))
left,right=0,maxs+1
def check(x):
    res=0
    for i in range(len(choc)):
        if choc[i][0]>=x and choc[i][1]>=x:
            res+=(choc[i][0]//x)*(choc[i][1]//x)
    if res<k:
        return False
    else:
        return True
while left+1<right:
    mid=(left+right)//2
    if check(mid):
        left=mid
    else:
        right=mid
if check(right):
    print(right)
else:
    print(left)