#include <bits/stdc++.h>
using namespace std;
const int MOD = (int)1e9 + 7;
const int FFTMOD = 119 << 23 | 1;
const int INF = (int)1e9 + 23111992;
const long long LINF = (long long)1e18 + 23111992;
const long double PI = acos((long double)-1);
const long double EPS = 1e-9;
inline long long gcd(long long a, long long b) {
  long long r;
  while (b) {
    r = a % b;
    a = b;
    b = r;
  }
  return a;
}
inline long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }
inline long long fpow(long long n, long long k, int p = MOD) {
  long long r = 1;
  for (; k; k >>= 1) {
    if (k & 1) r = r * n % p;
    n = n * n % p;
  }
  return r;
}
template <class T>
inline int chkmin(T& a, const T& val) {
  return val < a ? a = val, 1 : 0;
}
template <class T>
inline int chkmax(T& a, const T& val) {
  return a < val ? a = val, 1 : 0;
}
inline unsigned long long isqrt(unsigned long long k) {
  unsigned long long r = sqrt(k) + 1;
  while (r * r > k) r--;
  return r;
}
inline long long icbrt(long long k) {
  long long r = cbrt(k) + 1;
  while (r * r * r > k) r--;
  return r;
}
inline void addmod(int& a, int val, int p = MOD) {
  if ((a = (a + val)) >= p) a -= p;
}
inline void submod(int& a, int val, int p = MOD) {
  if ((a = (a - val)) < 0) a += p;
}
inline int mult(int a, int b, int p = MOD) { return (long long)a * b % p; }
inline int inv(int a, int p = MOD) { return fpow(a, p - 2, p); }
inline int sign(long double x) { return x < -EPS ? -1 : x > +EPS; }
inline int sign(long double x, long double y) { return sign(x - y); }
mt19937 mt(chrono::high_resolution_clock::now().time_since_epoch().count());
inline int myrand() { return abs((int)mt()); }
void chemthan() {
  int n;
  cin >> n;
  string a, b;
  cin >> a >> b;
  vector<int> f(n - 1);
  for (int i = (0); i < (n - 1); ++i) {
    int off = i ? f[i - 1] : 0;
    f[i] = b[i] - a[i] - off;
  }
  if (f[n - 2] ^ b[n - 1] - a[n - 1]) {
    cout << -1 << "\n";
    return;
  }
  long long sum = 0;
  for (int i = (0); i < (n - 1); ++i) sum += abs(f[i]);
  cout << sum << "\n";
  vector<pair<int, int> > res;
  for (int i = (0); i < (n - 1); ++i) {
    while ((a[i] ^ b[i]) && int((res).size()) < 1e5) {
      vector<pair<int, int> > tmp;
      int sign = a[i] < b[i] ? 1 : -1;
      a[i] += sign;
      for (int j = (i); j < (n - 1); ++j) {
        if (sign == 1) {
          tmp.push_back({j, 1});
          if (a[j + 1] < '9') {
            a[j + 1]++;
            break;
          }
        } else {
          tmp.push_back({j, -1});
          if (a[j + 1] > '0') {
            a[j + 1]--;
            break;
          }
        }
        sign *= -1;
      }
      reverse((tmp).begin(), (tmp).end());
      for (pair<int, int> e : tmp) res.push_back(e);
    }
  }
  if (int((res).size()) > 1e5) {
    res.resize((int)1e5);
  }
  for (pair<int, int> e : res) {
    cout << e.first + 1 << " " << e.second << "\n";
  }
}
int main(int argc, char* argv[]) {
  ios_base::sync_with_stdio(0), cin.tie(0);
  if (argc > 1) {
    assert(freopen(argv[1], "r", stdin));
  }
  if (argc > 2) {
    assert(freopen(argv[2], "wb", stdout));
  }
  chemthan();
  cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
  return 0;
}
