# correct

M = 10 ** 6 + 10

n = int(input())

W = [0] * (2 * M + 1)

for _ in range(n):
    a, b = map(int, input().split())
    W[M + a + 1] += 1
    W[M + b + 1] -= 1
    W[M + a - b + 1] -= 1

# accumulate
for i in range(2 * M):
    W[i + 1] += W[i]

S = [0] * (M + 1)
S[0] = W[M]
for i in range(1, M + 1):
    S[i] = W[M - i] + W[M + i]

del W

# zeta transform
is_prime = [True] * (M + 1)
for p in range(2, M + 1):
    if not is_prime[p]:
        continue
    q = M // p
    while q >= p:
        is_prime[p * q] = False  # sieve
        S[q] += S[p * q]
        q -= 1
    while q >= 1:
        S[q] += S[p * q]
        q -= 1

max_f, argmax = -1, 0

for m in range(1, M + 1):
    f_m = -n * (M // m) - S[0] - S[m]
    if f_m > max_f:
        max_f, argmax = f_m, m
print(argmax)