#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define endl '\n'
#define boostIO() ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
ll gcd(ll a, ll b) { return (b == 0 ? a : gcd(b, a % b)); }

signed main() {
    int n, count = 0;
    ll mod = 1e9 + 7;
    string s;
    cin >> n >> s;
    for (auto ch : s) if (ch == '?') ++count;
    vector<vector<vector<ll>>> dp(n + 1, vector<vector<ll>>(4, vector<ll>(4)));
    vector<ll> v(n + 1, 1);
    for (int i = 1; i <= n; ++i) {
        v[i] = (v[i - 1] * 3) % mod;
    }

    dp[0][0][0] = 1;
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j <= 3; ++j) {
            for (int k = 0; k <= 3; ++k) {
                if (dp[i][j][k]) {
                    dp[i + 1][j][k] += dp[i][j][k];
                    dp[i + 1][j][k] %= mod;
                    if (j < 3 && (s[i] == '?' || s[i] - 'a' == j)) {
                        int nk = (s[i] == '?' ? k + 1 : k);
                        dp[i + 1][j + 1][nk] += dp[i][j][k];
                        dp[i + 1][j + 1][nk] %= mod;
                    }
                }
            }
        }
    }
    ll ans = 0;
    for (int i = 0; i <= 3; ++i) {
        if (count >= i) {
            ans += (dp[n][3][i] * v[count - i]) % mod;
            ans %= mod;
        }
    }
    cout << ans;
}