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

typedef long long ll;
typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<vector<vector<ll>>> vvvll;
typedef vector<bool> vb;
typedef vector<vector<bool>> vvb;
typedef vector<vector<vector<bool>>> vvvb;
typedef pair<ll, ll> pll;
typedef vector<pll> vpll;
typedef vector<vpll> vvpll;
typedef vector<double> vd;
typedef vector<vd> vdd;

#define FOR(i,x,y) for(ll i=(ll)x; i<(ll)y; ++i)
#define REP(i,y) FOR(i, 0, y)
#define RFOR(i,x,y) for(ll i=(ll)x; i>=(ll)y; --i)
#define RREP(i,x) RFOR(i, x, 0)
#define ALL(a) a.begin(), a.end()
#define pb push_back
#define debug_print(x...) cerr << "line " << __LINE__ << " : "; debug_print_in(x);

template <typename First>
void debug_print_in(First first){
  cerr << first << endl;
  return;
}

template <typename First, typename... Rest>
void debug_print_in(First first, Rest... rest){
  cerr << first << " ";
  debug_print_in(rest...);
  return;
}

void IN(void){
  return;
}

template <typename First, typename... Rest>
void IN(First& first, Rest&... rest){
  cin >> first;
  IN(rest...);
  return;
}

template <typename First>
void OUT(First first){
  cout << first << endl;
  return;
}

template <typename First, typename... Rest>
void OUT(First first, Rest... rest){
  cout << first << " ";
  OUT(rest...);
  return;
}

template<class t, class u> void chmax(t&a,u b){if(a<b)a=b;};
template<class t, class u> void chmin(t&a,u b){if(a>b)a=b;};
int popcount(int t){return __builtin_popcount(t);} //GCC
int popcount(ll t){return __builtin_popcountll(t);} //GCC

template <typename T>
void vec_print(vector<T> VEC){
  REP(i, VEC.size()){
    cerr << VEC[i] << " ";
  }
  cerr << endl;
};

template <typename T>
void mat_print(vector<vector<T> > MAT){
  REP(i,MAT.size()){
    REP(j,MAT[i].size()){
      cerr << MAT[i][j] << " ";
    }
    cerr << endl;
  }
};

constexpr int INF = (1<<30);
constexpr ll INFLL = 1LL<<62;
constexpr long double EPS = 1e-12;
constexpr ll MOD = (ll)((1E+9)+7);

string S;
ll N;
vvll dp;

void search(ll index){
  if(index>=N) return;
  if(S[index]=='A'){
    dp[index+1][0] = dp[index][0];
    dp[index+1][1] = (dp[index][1]+dp[index][0])%MOD;
    dp[index+1][2] = dp[index][2];
    dp[index+1][3] = dp[index][3];
  }else if(S[index]=='B'){
    dp[index+1][0] = dp[index][0];
    dp[index+1][1] = dp[index][1];
    dp[index+1][2] = (dp[index][2] + dp[index][1])%MOD;
    dp[index+1][3] = dp[index][3];
  }else if(S[index]=='C'){
    dp[index+1][0] = dp[index][0];
    dp[index+1][1] = dp[index][1];
    dp[index+1][2] = dp[index][2];
    dp[index+1][3] = (dp[index][3] + dp[index][2])%MOD;
  }else{
    dp[index+1][0] = (3*dp[index][0])%MOD;
    dp[index+1][1] = (3*dp[index][1]+dp[index][0])%MOD;
    dp[index+1][2] = (3*dp[index][2] + dp[index][1])%MOD;
    dp[index+1][3] = (3*dp[index][3] + dp[index][2])%MOD;
  }
  search(index+1);
  return;
}

int main(){
  cin.tie(0); // cut the cin and cout (default, std::flush is performed after std::cin)
  ios::sync_with_stdio(false); // cut the iostream and stdio (DON'T endl; BUT "\n";)

  IN(S);
  N = S.size();
  dp.resize(N+1, vll(4, 0));
  dp[0][0] = 1;

  search(0);

  //mat_print(dp);

  OUT(dp[N][3]%MOD);

  return 0;
}

Measured memory_bytes: 7376