import sys
input = sys.stdin.readline

N,M=map(int,input().split())

A=[list(map(int,input().split())) for i in range(N)]

DAY=[0]*(N+1)

for a,b in A:
    day=(M-a+1+b-1)//b
    DAY[min(day,N)]+=1

#print(DAY)

for i in range(1,N+1):
    DAY[i]+=DAY[i-1]

ANS=0
for i in range(1,N):
    ANS=max(ANS,(DAY[i]+i-1)//i)

print(ANS)