#include <bits/stdc++.h>
using namespace std;
const int inf = 1e9;
const int sigma = 26;
struct datum {
  string type;
  int pos;
  char l;
};
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  string s, t;
  cin >> s >> t;
  int m = (int)(t).size();
  int n = (int)(s).size();
  vector<vector<int> > dp(n + 1, vector<int>(m + 1, inf));
  vector<vector<int> > p(n + 1, vector<int>(m + 1, inf));
  for (int i = 0; i <= m; ++i) {
    dp[0][i] = i;
  }
  for (int i = 0; i < (int)(s).size(); ++i) {
    vector<int> pos(sigma, -1);
    dp[i + 1][0] = i + 1;
    p[i + 1][0] = -1;
    for (int j = 1; j <= m; ++j) {
      if (dp[i + 1][j] > dp[i][j] + 1) {
        dp[i + 1][j] = dp[i][j] + 1;
        p[i + 1][j] = -1;
      }
      if (dp[i + 1][j] > dp[i][j - 1] + 1) {
        dp[i + 1][j] = dp[i][j - 1] + 1;
        p[i + 1][j] = -2;
      }
      pos[t[j - 1] - 'A'] = j - 1;
      int x = pos[s[i] - 'A'];
      if (x != -1 && dp[i + 1][j] > dp[i][x] + j - x - 1) {
        dp[i + 1][j] = dp[i][x] + j - x - 1;
        p[i + 1][j] = x;
      }
    }
  }
  cout << dp[n][m] << endl;
  int i = n, j = m;
  vector<datum> ans;
  while (i > 0) {
    if (p[i][j] == -1) {
      ans.push_back({"DELETE", i, '-'});
      --i;
    } else if (p[i][j] == -2) {
      ans.push_back({"REPLACE", i, t[j - 1]});
      --i;
      --j;
    } else {
      int curr = p[i][j];
      for (int k = curr + 1, u = i + 1; k < j; ++k, ++u) {
        ans.push_back({"INSERT", u, t[k]});
      }
      --i;
      j = curr;
    }
  }
  for (int k = j - 1; k >= 0; --k) {
    ans.push_back({"INSERT", 1, t[k]});
  }
  for (int i = 0; i < (int)(ans).size(); ++i) {
    cout << ans[i].type << " " << ans[i].pos;
    if (ans[i].type != "DELETE") {
      cout << " " << ans[i].l;
    }
    cout << "\n";
  }
}
