#include <bits/stdc++.h>
using namespace std;
const int N = 1e3 + 5;
int n, m, dp[N][N], par[N][N];
string a, b;
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> a >> b;
  n = a.size(), m = b.size();
  for (int i = 0; i <= n; i++) {
    par[i][0] = 1;
    dp[i][0] = i;
  }
  for (int i = 0; i <= m; i++) {
    par[0][i] = 2;
    dp[0][i] = i;
  }
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      dp[i + 1][j + 1] = dp[i][j + 1] + 1;
      par[i + 1][j + 1] = 1;
      if (dp[i + 1][j + 1] > dp[i + 1][j] + 1) {
        dp[i + 1][j + 1] = dp[i + 1][j] + 1;
        par[i + 1][j + 1] = 2;
      }
      if (dp[i + 1][j + 1] > dp[i][j] + 1) {
        dp[i + 1][j + 1] = dp[i][j] + 1;
        par[i + 1][j + 1] = 3;
      }
      if (a[i] == b[j] && dp[i + 1][j + 1] > dp[i][j])
        dp[i + 1][j + 1] = dp[i][j], par[i + 1][j + 1] = 0;
    }
  }
  int x = n, y = m;
  cout << dp[n][m] << "\n";
  while (x || y) {
    int t = par[x][y];
    if (t == 0)
      x--, y--;
    else if (t == 1) {
      cout << "DELETE " << x << "\n";
      x--;
    } else if (t == 2) {
      cout << "INSERT " << x + 1 << " " << b[y - 1] << "\n";
      y--;
    } else {
      cout << "REPLACE " << x << " " << b[y - 1] << "\n";
      x--, y--;
    }
  }
}
