#include <bits/stdc++.h>
using namespace std;
const int N = 55;
const int M = 1e6 + 10;
const long long mod = 51123987;
const int INF = 2e9 + 1;
inline void rd(long long &x) {
  x = 0;
  char ch = getchar();
  bool flag = 0;
  while ((ch < '0' || ch > '9') && ch != '-') ch = getchar();
  if (ch == '-') flag = 1, ch = getchar();
  while (ch >= '0' && ch <= '9') x = x * 10ll + ch - '0', ch = getchar();
  if (flag) x = -x;
  return;
}
inline void rd(int &x) {
  x = 0;
  char ch = getchar();
  bool flag = 0;
  while ((ch < '0' || ch > '9') && ch != '-') ch = getchar();
  if (ch == '-') flag = 1, ch = getchar();
  while (ch >= '0' && ch <= '9') x = x * 10 + ch - '0', ch = getchar();
  if (flag) x = -x;
  return;
}
inline char rch() {
  char c;
  while ((c = getchar()) != '<' && c != '=')
    ;
  return c;
}
int n, tp[N * 3][3], dp[N * 3][N][N][N], a[N * 3], ans;
char ch[N * 3];
int main() {
  rd(n);
  scanf("%s", ch + 1);
  for (int i = 1; i <= n; ++i) {
    a[i] = ch[i] - 'a';
  }
  int MAXN = n / 3 + 2;
  for (int k = 0; k <= 2; ++k)
    for (int i = 0; i <= n; ++i) {
      for (int j = max(1, i); j <= n; ++j) {
        if (a[j] == k) {
          tp[i][k] = j;
          break;
        }
      }
    }
  dp[1][0][0][0] = 1;
  for (int i = 1; i <= n; ++i) {
    for (int a = 0; a <= MAXN; ++a) {
      for (int b = 0; b <= MAXN; ++b) {
        for (int c = 0; c <= MAXN; ++c) {
          if (tp[i][0]) {
            dp[tp[i][0]][a + 1][b][c] += dp[i][a][b][c];
            if (dp[tp[i][0]][a + 1][b][c] >= mod)
              dp[tp[i][0]][a + 1][b][c] -= mod;
          }
          if (tp[i][1]) {
            dp[tp[i][1]][a][b + 1][c] += dp[i][a][b][c];
            if (dp[tp[i][1]][a][b + 1][c] >= mod)
              dp[tp[i][1]][a][b + 1][c] -= mod;
          }
          if (tp[i][2]) {
            dp[tp[i][2]][a][b][c + 1] += dp[i][a][b][c];
            if (dp[tp[i][2]][a][b][c + 1] >= mod)
              dp[tp[i][2]][a][b][c + 1] -= mod;
          }
          if (a + b + c == n && abs(a - b) < 2 && abs(b - c) < 2 &&
              abs(a - c) < 2) {
            ans += dp[i][a][b][c];
            if (ans >= mod) ans -= mod;
          }
        }
      }
    }
  }
  ans = (ans % mod + mod) % mod;
  cout << ans << endl;
  return 0;
}
