#include <bits/stdc++.h>
using namespace std;
const long long N = 1007777;
long long inf = 2e18;
long long n, m;
long long x;
long long a[N];
long long b[N];
long long c[N];
vector<long long> ans;
bool check_eq() {
  for (long long i = 1; i <= n; i++) {
    if (a[i] != b[i]) {
      return 0;
    }
  }
  return 1;
}
bool check_eq_rev() {
  for (long long i = 1; i <= n; i++) {
    if (a[i] != b[n - i + 1]) {
      return 0;
    }
  }
  return 1;
}
bool check_up() {
  for (long long i = 2; i <= n; i++) {
    if (b[i] <= b[i - 1]) {
      return 0;
    }
  }
  return 1;
}
bool check_down() {
  for (long long i = 2; i <= n; i++) {
    if (b[i] >= b[i - 1]) {
      return 0;
    }
  }
  return 1;
}
void rvrs() {
  ans.push_back(0);
  for (long long i = 1; i <= n; i++) {
    c[i] = b[i];
  }
  for (long long i = 1; i <= n; i++) {
    b[i] = c[n - i + 1];
  }
}
bool check_may() {
  if (check_up()) {
    return 1;
  } else {
    if (check_down()) {
      rvrs();
      return 1;
    } else {
      return 0;
    }
  }
}
long long col = 0;
long long big = 2e5;
void print() {
  if (col > big) {
    cout << "BIG" << endl;
    cout << col << endl;
  } else {
    cout << "SMALL" << endl;
    cout << ans.size() << endl;
    if (ans.size() > 0)
      for (long long i = ans.size() - 1; i >= 0; i--) {
        if (ans[i] == 0) {
          cout << "R";
        } else {
          cout << "P";
        }
      }
  }
}
void reduce() {
  col++;
  ans.push_back(1);
  for (long long i = n; i >= 2; i--) {
    b[i] = b[i] - b[i - 1];
  }
}
bool check_min() {
  if (b[1] == min(a[1], a[2])) {
    return 1;
  } else {
    return 0;
  }
}
void solve_min() {
  long long x = max(a[1], a[2]);
  long long y = min(a[1], a[2]);
  if (x % y == b[2] % y) {
    long long k = (b[2] - x) / y;
    col += k;
    for (long long i = 0; i < k; i++) {
      ans.push_back(1);
      if (ans.size() > big) {
        break;
      }
    }
    if (a[1] > a[2]) {
      ans.push_back(0);
    }
    print();
  } else {
    cout << "IMPOSSIBLE" << endl;
  }
}
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  for (long long i = 1; i <= n; i++) {
    cin >> a[i];
  }
  for (long long i = 1; i <= n; i++) {
    cin >> b[i];
  }
  if (n == 1) {
    if (a[1] == b[1]) {
      cout << "SMALL" << endl;
      cout << 0 << endl;
    } else {
      cout << "IMPOSSIBLE" << endl;
    }
    return 0;
  }
  if (n == 2) {
    long long cnt = 0;
    while (true) {
      cnt++;
      if (check_eq()) {
        print();
        return 0;
      }
      if (check_eq_rev()) {
        ans.push_back(0);
        print();
        return 0;
      }
      check_may();
      if (b[1] == 0) {
        cout << "IMPOSSIBLE" << endl;
        return 0;
      }
      if (check_min()) {
        solve_min();
        return 0;
      } else {
        long long k = (b[2] - (b[2] % b[1])) / b[1];
        col += k;
        b[2] = b[2] % b[1];
        for (long long i = 0; i < k; i++) {
          ans.push_back(1);
          if (ans.size() > big) {
            break;
          }
        }
      }
    }
  } else {
    while (true) {
      if (check_eq()) {
        print();
        return 0;
      }
      if (check_eq_rev()) {
        ans.push_back(0);
        print();
        return 0;
      }
      if (!check_may()) {
        cout << "IMPOSSIBLE" << endl;
        return 0;
      }
      reduce();
    }
  }
}
