# Write a function to compute the value of ncr mod p.
def nCr_mod_p(n, r, p):
    if r > n - r:
        r = n - r
    C = [0 for i in range(r + 1)]
    C[0] = 1
    for i in range(1, n + 1):
        for j in range(min(i, r), 0, -1):
            C[j] = (C[j] + C[j - 1]) % p
    return C[r]
