//#define USEPB_DS
#define USETR1
#define CPPELEVEN
#define GPP

/*
 * temp.cpp
 *
 *  Created on: 2012-7-18
 *      Author: BSBandme
 */
//#pragma comment(linker, "/STACK:1024000000,1024000000")

#include <iostream>
#include <fstream>
#include <string.h>
#include <cstdio>
#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <cassert>
#include <list>
#include <iomanip>
#include <math.h>
#include <deque>
#include <utility>
#include <map>
#include <set>
#include <bitset>
#include <numeric>
#include <climits>
#include <cctype>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <functional>
#include <sstream>
#include <tuple>

using namespace std;

#ifndef CPPELEVEN
#ifdef USETR1
#include <tr1/unordered_map>
#include <tr1/unordered_set>
using namespace tr1;
#endif
#else
#include <unordered_map>
#include <unordered_set>
#endif

#ifdef USEPB_DS
#include <ext/pb_ds/priority_queue.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
// binomial_heap_tag, rc_binomial_heap_tag, thin_heap_tag, binary_heap_tag
typedef __gnu_pbds::priority_queue<int, greater<int>, pairing_heap_tag> pq_type;
// splay_tree_tag, ov_tree_tag
typedef tree <int, null_type, less <int>, rb_tree_tag, tree_order_statistics_node_update> tree_type;
#endif

#define mpr make_pair
typedef unsigned int ui;
typedef unsigned long long ull;
typedef long long ll;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;
typedef pair <double, double> pdd;
typedef vector <int> vi;
typedef vector <ll> vll;
typedef vector <double> vd;
typedef vector <string> vs;
typedef map <string, int> mpsi;
typedef map <double, int> mpdi;
typedef map <int, int> mpii;

const double pi = acos(0.0) * 2.0;
const long double eps = 1e-10;
const int step[8][2] = {{-1, 0}, {0, 1}, {1, 0}, {0, -1}, {-1, 1}, {1, 1}, {1, -1}, {-1, -1}};

template <class T> inline T abs1(T a) {return a < 0 ? -a : a;}

#ifndef CPPELEVEN
template <class T> inline T max1(T a, T b) { return b < a ? a : b; }
template <class T> inline T max1(T a, T b, T c) { return max1(max1(a, b), c); }
template <class T> inline T max1(T a, T b, T c, T d) { return max1(max1(a, b, c), d); }
template <class T> inline T max1(T a, T b, T c, T d, T e) { return max1(max1(a, b, c, d), e); }
template <class T> inline T min1(T a, T b) { return a < b ? a : b; }
template <class T> inline T min1(T a, T b, T c) { return min1(min1(a, b), c); }
template <class T> inline T min1(T a, T b, T c, T d) { return min1(min1(a, b, c), d); }
template <class T> inline T min1(T a, T b, T c, T d, T e) { return min1(min1(a, b, c, d), e); }
#else
template <typename t, typename t1>
t min1(t a, t1 b) { return a < b ? a : b; }
template <typename t, typename... arg>
t min1(t a, arg... arr) { return min1(a, min1(arr...)); }
template <typename t, typename t1>
t max1(t a, t1 b) { return a > b ? a : b; }
template <typename t, typename... arg>
t max1(t a, arg... arr) { return max1(a, max1(arr...)); }
#endif

inline int jud(double a, double b){
	if(abs(a) < eps && abs(b) < eps) return 0;
	else if(abs1(a - b) / max(abs1(a), abs1(b)) < eps) return 0;
	if(a < b) return -1;
	return 1;
}
template <typename t> inline int jud(t a, t b){
	if(a < b) return -1;
	if(a == b) return 0;
	return 1;
}

// f_lb == 1代表返回相同的一串的左边界，f_small == 1代表返回如果没有寻找的值返回小的数
template <typename it, typename t1>
inline int find(t1 val, it a, int na, bool f_small = 1, bool f_lb = 1){
	if(na == 0) return 0;
	int be = 0, en = na - 1;
	if(*a <= *(a + na - 1)){
		if(f_lb == 0) while(be < en){
			int mid = (be + en + 1) / 2;
			if(jud(*(a + mid), val) != 1) be = mid;
			else en = mid - 1;
		}else while(be < en){
			int mid = (be + en) / 2;
			if(jud(*(a + mid), val) != -1) en = mid;
			else be = mid + 1;
		}
		if(f_small && jud(*(a + be), val) == 1) be--;
		if(!f_small && jud(*(a + be), val) == -1) be++;
	} else {
		if(f_lb) while(be < en){
			int mid = (be + en + 1) / 2;
			if(jud(*(a + mid), val) != -1) be = mid;
			else en = mid - 1;
		}else while(be < en){
			int mid = (be + en) / 2;
			if(jud(*(a + mid), val) != 1) en = mid;
			else be = mid + 1;
		}
		if(!f_small && jud(*(a + be), val) == -1) be--;
		if(f_small && jud(*(a + be), val) == 1) be++;
	}
	return be;
}

template <class T> inline T lowb(T num) {return num & (-num); }
#ifdef GPP
inline int bitnum(ui nValue) { return __builtin_popcount(nValue); }
inline int bitnum(int nValue) { return __builtin_popcount(nValue); }
inline int bitnum(ull nValue) { return __builtin_popcount(nValue) + __builtin_popcount(nValue >> 32); }
inline int bitnum(ll nValue) { return __builtin_popcount(nValue) + __builtin_popcount(nValue >> 32); }
inline int bitmaxl(ui a) { if(a == 0) return 0; return 32 - __builtin_clz(a); }
inline int bitmaxl(int a) { if(a == 0) return 0; return 32 - __builtin_clz(a); }
inline int bitmaxl(ull a) { int temp = a >> 32; if(temp) return 32 - __builtin_clz(temp) + 32; return bitmaxl(int(a)); }
inline int bitmaxl(ll a) { int temp = a >> 32; if(temp) return 32 - __builtin_clz(temp) + 32; return bitmaxl(int(a)); }
#else
#endif

long long pow(long long n, long long m, long long mod = 0){
	if(m < 0) return 0;
	long long ans = 1;
	long long k = n;
	while(m){
		if(m & 1) {
			ans *= k;
			if(mod) ans %= mod;
		}
		k *= k;
		if(mod) k %= mod;
		m >>= 1;
	}
	return ans;
}

#define  MOD 1000000007
template <class t1, class t2>
inline void add(t1 &a, t2 b, int mod = -1) {
	if(mod == -1) mod = MOD;
	a += b;
	while(a >= mod) a -= mod;
	while(a < 0) a += mod;
}
template <class t>
void output1(t arr) {
	for(int i = 0; i < (int)arr.size(); i++)
		cerr << arr[i] << ' ';
	cerr << endl;
}
template <class t>
void output2(t arr) {
	for(int i = 0; i < (int)arr.size(); i++)
		output1(arr[i]);
}

//....................密..........封..........线..........下..........禁..........止..........hack...............................................

const int maxn = 501000;
ll fac[maxn];

const int mod = MOD;


int n, arr[maxn];
ll have[maxn];
ll small[maxn];

#ifndef N
#define N 1 << 21
#endif
template <class t> struct tree_array{
	t num[N], n, bigwei;
	void init(int nn = N){
		n = nn;
		while(lowb(nn) != nn) nn -= lowb(nn);
		bigwei = nn;
		n = bigwei * 2;
	}
	void upd(int no, t add){
		while(no <= n){
			num[no] += add;
			no += lowb(no);
		}
	}
	t que(int no){
		t ans = 0;
		while(no){
			ans += num[no];
			no -= lowb(no);
		}
		return ans;
	}
	 int getrank(t x){
		 int ans = 0, ranwei = bigwei; t rank = 0;
		 while(ranwei){
			 if(rank + num[ranwei + ans] < x){
				 ans += ranwei;
				 rank += num[ans];
			 }
			 ranwei >>= 1;
		 }
		 return ans + 1;
	 }
};
tree_array <int> ta;


int main() {

//............................不要再忘了检查maxn大小了！！！！BSBandme你个SB！！！！...................................................

	ios_base::sync_with_stdio(0);
	#ifdef DEBUG //......................................................................................................
	freopen("input.txt", "r", stdin);
	#endif //...........................................................................................................

	fac[0] = 1;
	for(int i = 1; i < maxn; i++)
		fac[i] = fac[i - 1] * i % mod;

	scanf("%d", &n);
	for(int i = 0; i < n; i++) {
		scanf("%d", arr + i);
	}
	for(int i = 0; i < n; i++)
		have[arr[i]] = 1;
	ll sum = 0;
	for(int i = 1; i <= n; i++) {
		if(!have[i]) {
			small[i]++;
		}
		small[i] += small[i - 1];
	}
	ta.init(maxn + 2);
	ll ans = 0, already = 0;
	for(int i = n - 1; i >= 0; i--) {
		if(arr[i] == 0) {
			ll rsum = sum * fac[small[n] - 1] % mod;
			if(small[n] >= 2)
				add(rsum, already * (small[n] * (small[n] - 1) / 2 % mod) % mod * fac[small[n] - 2] % mod);
			ans += rsum * fac[n - 1 - i] % mod;
			ans %= mod;
			already++;
		} else {
			add(sum, small[n] - small[arr[i]]);
			add(ans, (already * small[arr[i]] % mod * fac[small[n] - 1] % mod) % mod * fac[n - 1 - i] % mod);
			add(ans, ta.que(arr[i]) * fac[n - 1 - i] % mod * fac[small[n]] % mod);
			ta.upd(arr[i], 1);
		}
	}
	add(ans, fac[already]);
	cout << ans << endl;

    return 0;
}



Measured memory_bytes: 16000