Ivan unexpectedly saw a present from one of his previous birthdays. It is array of n numbers from 1 to 200. Array is old and some numbers are hard to read. Ivan remembers that for all elements at least one of its neighbours ls not less than it, more formally:

a_{1} ≤ a_{2},

a_{n} ≤ a_{n-1} and

a_{i} ≤ max(a_{i-1},    a_{i+1}) for all i from 2 to n-1.

Ivan does not remember the array and asks to find the number of ways to restore it. Restored elements also should be integers from 1 to 200. Since the number of ways can be big, print it modulo 998244353.

Input

First line of input contains one integer n (2 ≤ n ≤ 10^{5}) — size of the array.

Second line of input contains n integers a_{i} — elements of array. Either a_{i} = -1 or 1 ≤ a_{i} ≤ 200. a_{i} = -1 means that i-th element can't be read.

Output

Print number of ways to restore the array modulo 998244353.

Examples

Input

3
1 -1 2


Output

1


Input

2
-1 -1


Output

200

Note

In the first example, only possible value of a_{2} is 2.

In the second example, a_{1} = a_{2} so there are 200 different values because all restored elements should be integers between 1 and 200. 
#include <bits/stdc++.h>
using namespace std;
const double PI = acos(-1);
const double eps = 1e-12;
const int inf = 2000000000;
const long long int infLL = (long long int)2e18;
long long int MOD = 998244353;
int MOD1 = 1000000007;
int MOD2 = 1000000009;
inline bool checkBit(long long int n, long long int i) {
  return n & (1LL << i);
}
inline long long int setBit(long long int n, long long int i) {
  return n | (1LL << i);
  ;
}
inline long long int resetBit(long long int n, long long int i) {
  return n & (~(1LL << i));
}
int dx[] = {0, 0, +1, -1};
int dy[] = {+1, -1, 0, 0};
inline bool EQ(double a, double b) { return fabs(a - b) < 1e-9; }
inline bool isLeapYear(long long int year) {
  return (year % 400 == 0) || (year % 4 == 0 && year % 100 != 0);
}
inline void normal(long long int &a) {
  a %= MOD;
  (a < 0) && (a += MOD);
}
inline long long int modMul(long long int a, long long int b) {
  a %= MOD, b %= MOD;
  normal(a), normal(b);
  return (a * b) % MOD;
}
inline long long int modAdd(long long int a, long long int b) {
  a %= MOD, b %= MOD;
  normal(a), normal(b);
  return (a + b) % MOD;
}
inline long long int modSub(long long int a, long long int b) {
  a %= MOD, b %= MOD;
  normal(a), normal(b);
  a -= b;
  normal(a);
  return a;
}
inline long long int modPow(long long int b, long long int p) {
  long long int r = 1LL;
  while (p) {
    if (p & 1) r = modMul(r, b);
    b = modMul(b, b);
    p >>= 1LL;
  }
  return r;
}
inline long long int modDiv(long long int a, long long int b) {
  return modMul(a, modPow(b, MOD - 2));
}
bool comp(const pair<long long int, pair<long long int, long long int> > &p1,
          const pair<long long int, pair<long long int, long long int> > &p2) {
  return p1.first > p2.first;
}
bool comp1(const pair<long long int, long long int> &p1,
           const pair<long long int, long long int> &p2) {
  if (p1.first == p2.first) {
    return p1.second > p2.second;
  }
  return p1.first < p2.first;
}
long long int converter(string a) {
  long long int i, mul = 1, r, t, ans = 0LL;
  if (a.length() == 0) return 0;
  for (i = a.length() - 1; i >= 0; i--) {
    t = a[i] - '0';
    r = t % 10;
    ans += (mul * r);
    mul = mul * 10;
  }
  return ans;
}
int msb(unsigned x) {
  union {
    double a;
    int b[2];
  };
  a = x;
  return (b[1] >> 20) - 1023;
}
const int MAX = (int)1e5 + 1;
int a[MAX];
long long int dp[2][201], sum[2][201];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  int n, i, j, ok;
  cin >> n;
  for (i = 1; i <= n; ++i) cin >> a[i];
  if (a[1] == -1) {
    for (i = 1; i <= 200; ++i) {
      dp[0][i] = 1;
      sum[0][i] = 1;
    }
  } else {
    dp[0][a[1]] = 1;
    sum[0][a[1]] = 1;
  }
  for (i = 1; i <= 200; ++i) {
    sum[0][i] += sum[0][i - 1];
    sum[1][i] += sum[1][i - 1];
  }
  for (i = 2; i <= n; ++i) {
    for (j = 1; j <= 200; ++j) {
      dp[0][j] = (sum[1][j - 1] + sum[0][j - 1]);
      dp[1][j] = (sum[1][200] - sum[1][j - 1] + MOD) +
                 (sum[0][j] - sum[0][j - 1] + MOD);
      dp[0][j] %= MOD;
      dp[1][j] %= MOD;
    }
    memset(sum, 0, sizeof(sum));
    for (j = 1; j <= 200; ++j) {
      if (a[i] == -1 || a[i] == j) {
        sum[0][j] = dp[0][j];
        sum[1][j] = dp[1][j];
      } else {
        dp[0][j] = 0;
        dp[1][j] = 0;
      }
      sum[0][j] += sum[0][j - 1];
      sum[1][j] += sum[1][j - 1];
      sum[0][j] %= MOD;
      sum[1][j] %= MOD;
    }
  }
  long long int ans = 0LL;
  for (i = 1; i <= 200; ++i) {
    ans += dp[1][i];
    ans %= MOD;
  }
  cout << ans << '\n';
  return 0;
}
