#include <bits/stdc++.h>
using namespace std;
const long double PI = 3.141592653589793238462643383279502884;
const long long PRIME1 = 1e9 + 7;
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
long long a[200010], b[200010];
void rev(long long *x, int n) {
  for (int i = 0; i < n / 2; i++) {
    swap(x[i], x[n - i - 1]);
  }
}
void pref_back(long long *x, int n) {
  for (int i = n - 1; i > 0; i--) {
    x[i] -= x[i - 1];
  }
}
bool checksort(long long *x, int n) {
  bool f = 1;
  int i = 0;
  while (f && i < (n - 1)) {
    f = x[i + 1] > x[i];
    i++;
  }
  return f;
}
bool checksort_back(long long *x, int n) {
  bool f = 1;
  int i = 0;
  while (f && i < (n - 1)) {
    f = x[i + 1] < x[i];
    i++;
  }
  return f;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  int i;
  for (i = 0; i < n; i++) {
    cin >> a[i];
  }
  for (i = 0; i < n; i++) {
    cin >> b[i];
  }
  if (n == 1) {
    if (a[0] == b[0]) {
      cout << "SMALL"
           << "\n"
           << 0;
    } else {
      cout << "IMPOSSIBLE";
    }
    return 0;
  }
  if (n == 2) {
    string s0 = "";
    long long count = 0;
    if (!checksort(a, n) && !checksort(b, n) && a[0] == b[0] && a[1] == b[1]) {
      cout << "SMALL"
           << "\n"
           << 0 << "\n";
      return 0;
    }
    if (!checksort(b, n)) {
      rev(b, n);
      s0 += "R";
    }
    bool f1 = 0;
    if (a[0] > a[1]) {
      rev(a, n);
      f1 = 1;
    }
    if (a[0] <= b[0] && a[1] <= b[1] && (gcd(a[1], a[0]) == gcd(b[1], b[0]))) {
      long long g = gcd(a[1], a[0]);
      a[1] /= g;
      a[0] /= g;
      b[0] /= g;
      b[1] /= g;
      while (a[0] < b[0] || a[1] < b[1]) {
        if (a[0] == b[0]) {
          if ((b[1] % a[0]) == (a[1] % a[0])) {
            count += (b[1] - a[1]) / a[0];
            if (count <= 200000) {
              for (i = 0; i < ((b[1] - a[1]) / a[0]); i++) {
                s0 += "P";
              }
            }
            b[1] = a[1];
          } else {
            cout << "IMPOSSIBLE";
            return 0;
          }
        } else {
          count += b[1] / b[0];
          if (count <= 200000) {
            for (i = 0; i < (b[1] / b[0]); i++) {
              s0 += "P";
            }
          }
          b[1] %= b[0];
          swap(b[1], b[0]);
          s0 += "R";
        }
      }
      if (f1) {
        s0 += "R";
      }
      if (count > 200000) {
        cout << "BIG"
             << "\n"
             << count;
      } else {
        reverse(s0.begin(), s0.end());
        cout << "SMALL"
             << "\n"
             << s0.length() << "\n"
             << s0;
      }
    } else {
      cout << "IMPOSSIBLE";
      return 0;
    }
    return 0;
  }
  if (n > 2) {
    long long count = 0;
    string s0 = "";
    bool f1 = 1;
    for (int i = 0; i < n && f1; i++) {
      f1 = a[i] == b[i];
    }
    if (f1) {
      cout << "SMALL"
           << "\n"
           << 0 << "\n";
      return 0;
    }
    f1 = 1;
    for (int i = 0; i < n && f1; i++) {
      f1 = a[i] == b[n - i - 1];
    }
    if (f1) {
      cout << "SMALL"
           << "\n"
           << 1 << "\n"
           << "R";
      return 0;
    }
    while (1) {
      if (!checksort(b, n)) {
        if (checksort_back(b, n)) {
          rev(b, n);
          pref_back(b, n);
          count++;
          if (count <= 200000) {
            s0 += "RP";
          }
        } else {
          cout << "IMPOSSIBLE";
          return 0;
        }
      } else {
        pref_back(b, n);
        count++;
        if (count <= 200000) {
          s0 += "P";
        }
      }
      f1 = 1;
      for (int i = 0; i < n && f1; i++) {
        f1 = a[i] == b[n - i - 1];
      }
      if (f1) {
        s0 += "R";
        break;
      }
      f1 = 1;
      for (int i = 0; i < n && f1; i++) {
        f1 = a[i] == b[i];
      }
      if (f1) {
        break;
      }
      f1 = 1;
      for (int i = 0; i < n && f1; i++) {
        f1 = b[i] > 0;
      }
      if (!f1) {
        cout << "IMPOSSIBLE";
        return 0;
      }
    }
    if (count <= 200000) {
      reverse(s0.begin(), s0.end());
      cout << "SMALL"
           << "\n"
           << s0.length() << "\n"
           << s0;
    } else {
      cout << "BIG"
           << "\n"
           << count << "\n";
    }
  }
  return 0;
}
