MOD = 10**9 + 7

def main():
    import sys
    input = sys.stdin.read().split()
    n = int(input[0])
    p = list(map(int, input[1:n+1]))
    
    visited = [False] * (n + 1)
    cycle_freq = {}
    for i in range(1, n+1):
        if not visited[i]:
            cnt = 0
            j = i
            while not visited[j]:
                visited[j] = True
                j = p[j-1]
                cnt += 1
            if cnt not in cycle_freq:
                cycle_freq[cnt] = 0
            cycle_freq[cnt] += 1
    
    has_even = False
    has_odd_multiple = False
    for l in cycle_freq:
        if l % 2 == 0:
            has_even = True
            break
        if cycle_freq[l] >= 2:
            has_odd_multiple = True
            break
    
    if has_even or has_odd_multiple:
        fact = [1] * (n + 1)
        for i in range(1, n+1):
            fact[i] = fact[i-1] * i % MOD
        
        denominator = 1
        for l in cycle_freq:
            m = cycle_freq[l]
            term = pow(l, m, MOD)
            term = term * pow(fact[m], 1, MOD) % MOD
            denominator = denominator * term % MOD
        
        inv_denominator = pow(denominator, MOD-2, MOD)
        K = fact[n] * inv_denominator % MOD
        print(K % MOD)
    else:
        fact = [1] * (n + 1)
        for i in range(1, n+1):
            fact[i] = fact[i-1] * i % MOD
        
        denominator = 1
        for l in cycle_freq:
            m = cycle_freq[l]
            term = pow(l, m, MOD)
            term = term * pow(fact[m], 1, MOD) % MOD
            denominator = denominator * term % MOD
        
        inv_denominator = pow(denominator, MOD-2, MOD)
        K = fact[n] * inv_denominator % MOD
        
        if K % 2 == 0:
            res = K * pow(2, MOD-2, MOD) % MOD
        else:
            res = 1
        print(res % MOD)

if __name__ == '__main__':
    main()