#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
const long long inf = mod * mod;
const long long d2 = (mod + 1) / 2;
const double EPS = 1e-10;
const double INF = 1e+10;
const double PI = acos(-1.0);
const int C_SIZE = 3121000;
namespace {
long long fact[C_SIZE];
long long finv[C_SIZE];
long long inv[C_SIZE];
long long Comb(int a, int b) {
  if (a < b || b < 0) return 0;
  return fact[a] * finv[b] % mod * finv[a - b] % mod;
}
void init_C(int n) {
  fact[0] = finv[0] = inv[1] = 1;
  for (int i = 2; i < n; i++) {
    inv[i] = (mod - (mod / i) * inv[mod % i] % mod) % mod;
  }
  for (int i = 1; i < n; i++) {
    fact[i] = fact[i - 1] * i % mod;
    finv[i] = finv[i - 1] * inv[i] % mod;
  }
}
long long pw(long long a, long long b) {
  if (a < 0LL) return 0;
  if (b < 0LL) return 0;
  long long ret = 1;
  while (b) {
    if (b % 2) ret = ret * a % mod;
    a = a * a % mod;
    b /= 2;
  }
  return ret;
}
long long pw_mod(long long a, long long b, long long M) {
  if (a < 0LL) return 0;
  if (b < 0LL) return 0;
  long long ret = 1;
  while (b) {
    if (b % 2) ret = ret * a % M;
    a = a * a % M;
    b /= 2;
  }
  return ret;
}
int pw_mod_int(int a, int b, int M) {
  if (a < 0) return 0;
  if (b < 0) return 0;
  int ret = 1;
  while (b) {
    if (b % 2) ret = (long long)ret * a % M;
    a = (long long)a * a % M;
    b /= 2;
  }
  return ret;
}
int ABS(int a) { return max(a, -a); }
long long ABS(long long a) { return max(a, -a); }
double ABS(double a) { return max(a, -a); }
int sig(double r) { return (r < -EPS) ? -1 : (r > +EPS) ? +1 : 0; }
}  // namespace
char in[110000];
long long dp[110000];
vector<int> v[3];
int sum[110000];
int main() {
  scanf("%s", in);
  int n = strlen(in);
  bool ok = true;
  for (int i = 1; i < n; i++) {
    if (in[i] == in[i - 1]) {
      ok = false;
      sum[i + 1]++;
    }
  }
  for (int i = 0; i <= n; i++) {
    sum[i + 1] += sum[i];
  }
  if (ok) {
    printf("1\n");
    return 0;
  }
  int t = 0;
  for (int i = 0; i < n; i++) {
    if (in[i] == 'a')
      t++;
    else
      t += 2;
    v[t % 3].push_back(i + 1);
  }
  dp[0] = 1;
  int now = 0;
  for (int i = 0; i < n; i++) {
    if (dp[i] == 0) continue;
    int left, right;
    left = -1;
    right = v[(now + 1) % 3].size();
    while (left + 1 < right) {
      int M = (left + right) / 2;
      int to = v[(now + 1) % 3][M];
      bool dame = false;
      if (to <= i) dame = true;
      if (to - i > 1 && sum[to] - sum[i + 1] == 0) dame = true;
      if (dame) {
        left = M;
      } else
        right = M;
    }
    if (right < v[(now + 1) % 3].size()) {
      dp[v[(now + 1) % 3][right]] = (dp[v[(now + 1) % 3][right]] + dp[i]) % mod;
    }
    left = -1;
    right = v[(now + 2) % 3].size();
    while (left + 1 < right) {
      int M = (left + right) / 2;
      int to = v[(now + 2) % 3][M];
      bool dame = false;
      if (to <= i) dame = true;
      if (to - i > 1 && sum[to] - sum[i + 1] == 0) dame = true;
      if (dame) {
        left = M;
      } else
        right = M;
    }
    if (right < v[(now + 2) % 3].size()) {
      dp[v[(now + 2) % 3][right]] = (dp[v[(now + 2) % 3][right]] + dp[i]) % mod;
    }
    if (in[i] == 'a')
      now++;
    else
      now += 2;
  }
  int s = 0;
  long long ret = 0;
  for (int i = 1; i <= n; i++) {
    if (in[i - 1] == 'a')
      s++;
    else
      s += 2;
    if (t % 3 == s % 3) {
      ret = (ret + dp[i]) % mod;
    }
  }
  printf("%lld\n", ret);
}
