#include <bits/stdc++.h>
using namespace std;

#define all(x) begin(x), end(x)
#ifdef CKISEKI
#define safe cerr << __PRETTY_FUNCTION__ << " line " << __LINE__ << " safe\n"
#define debug(a...) debug_(#a, a)
#define orange(a...) orange_(#a, a)
void debug_(auto s, auto ...a) {
  cerr << "\e[1;32m(" << s << ") = (";
  int f = 0;
  (..., (cerr << (f++ ? ", " : "") << a));
  cerr << ")\e[0m\n";
}
#include <experimental/iterator>
void orange_(auto s, auto L, auto R) {
  cerr << "\e[1;33m[ " << s << " ] = [ ";
  using namespace experimental;
  copy(L, R, make_ostream_joiner(cerr, ", "));
  cerr << " ]\e[0m\n";
}
#else
#define safe ((void)0)
#define debug(...) safe
#define orange(...) safe
#endif

const int maxn = 53;
int64_t dp[maxn][maxn][maxn][maxn];

int64_t pre[maxn][maxn][maxn][maxn]; // prefix sum by third dim

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int n;
  while (cin >> n) {

    vector<int> p(n + 1);
    for (int i = 1; i <= n; i++) {
      cin >> p[i];
    }

    for (int i = 0; i <= n + 1; i++) {
      for (int j = 0; j <= n + 1; j++) {
        for (int u = 0; u <= n + 1; u++) {
          for (int d = 0; d <= n + 1; d++) {
            dp[i][j][u][d] = 0;
            pre[i][j][u][d] = 0;
          }
        }
      }
    }
    
    for (int i = 0; i <= n; i++) {
      for (int x = 0; x <= n + 1; x++)
        for (int d = 0; d <= n + 1; d++)
          pre[i + 1][i][x][d] = 1;
    }

    for (int i = n; i >= 1; i--) {
      for (int j = i; j <= n; j++) {
        for (int d = 1; d <= n; d++) {
          for (int u = i; u <= j; u++) if (p[u] >= d) {

            dp[i][j][p[u]][d] += pre[u + 1][j][ p[u] ][d];

            for (int z = i; z < u; z++) if (p[z] >= d && p[z] < p[u]) {
              dp[i][j][p[u]][d]
                += dp[i][u - 1][p[z]][d] * pre[u + 1][j][ p[u] ][p[z] + 1];
            }
          }

        }

        for (int d = 0; d <= n + 1; d++) {
          pre[i][j][0][d] = 1;
          for (int c = 1; c <= n; c++)
            pre[i][j][c][d] = pre[i][j][c - 1][d] + dp[i][j][c][d];
        }
      }

    }

    int64_t ans = 0;

    for (int i = 1; i <= n; i++) {
      ans += dp[1][n][i][1];
      debug(dp[1][n][i][1]);
    }
    cout << ans << '\n';
  }

  return 0;
}