L, R, M = map(int, input().split())

ans = (M-2) * (R - L + 1) % M

C = 1
for i in range(1, L+1):
    C *= (L+i)
    C //= i
for i in range(L, R+1):
    ans += C
    ans %= M
    C *= (2 * i + 1)*(2 * i + 2)
    C //= (i + 1)*(i+1)

print(ans)