N, L = list(map(int, input().strip().split(' ')))
ans = 0
NMAX = L // (N - 1)
nonprime = [False] * (NMAX + 1)
for i in range(6, len(nonprime), 6):
    if nonprime[i - 1] and nonprime[i + 1]:
        continue
    if not nonprime[i - 1]:
        k = L - (i - 1) * (N - 1)
        if k < 0:
            break
        ans += k + 1
        j = 3
        x = i - 1
        while x * j <= NMAX:
            nonprime[x * j] = True
            j += 2
    if not nonprime[i + 1]:
        k = L - (i + 1) * (N - 1)
        if k < 0:
            break
        ans += k + 1
        j = 3
        x = i + 1
        while x * j <= NMAX:
            nonprime[x * j] = True
            j += 2
if 2 * (N - 1) <= L:
    ans += L - 2 * (N - 1) + 1
if 3 * (N - 1) <= L:
    ans += L - 3 * (N - 1) + 1
print(ans)