#include <bits/stdc++.h>
using namespace std;
const int N = 3e5 + 5, mod = 998244353;
template <class o>
inline void qr(o &x) {
  x = 0;
  char c = getchar();
  int f = 1;
  while (c < '0' || c > '9') {
    if (c == '-') f = -1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') {
    x = x * 10 + (c ^ 48);
    c = getchar();
  }
  x *= f;
}
template <class o>
void qw(o x) {
  if (x / 10) qw(x / 10);
  putchar(x % 10 + 48);
}
template <class o>
void pr1(o x) {
  if (x < 0) putchar('-'), x = -x;
  qw(x);
  putchar(' ');
}
template <class o>
void pr2(o x) {
  if (x < 0) putchar('-'), x = -x;
  qw(x);
  puts("");
}
inline int ksm(int a, int b = mod - 2) {
  int ans = 1;
  for (; b; b >>= 1, a = 1ll * a * a % mod)
    if (b & 1) ans = 1ll * ans * a % mod;
  return ans;
}
inline int add(int a, int b) { return a += b, a >= mod ? a - mod : a; }
inline int sub(int a, int b) { return a -= b, a < 0 ? a + mod : a; }
char s[N], t[N];
long long a[N], b[N], c[N];
void solve() {
  int n;
  qr(n);
  scanf("%s%s", s + 1, t + 1);
  for (int i = 1; i <= n; ++i) a[i] = s[i] - 48;
  for (int i = 1; i <= n; ++i) b[i] = t[i] - 48;
  long long ans = 0;
  for (int i = 1; i <= n; ++i)
    c[i] = b[i] - (a[i] + c[i - 1]), ans += abs(c[i]);
  if (c[n]) {
    puts("-1");
    return;
  }
  int p = 1, cur = 1;
  pr2(ans);
  ans = min(ans, 100000ll);
  while (ans--) {
    while (!c[p]) ++p, ++cur;
    while ((c[cur] > 0 && a[cur + 1] == 9) || (c[cur] < 0 && a[cur + 1] == 0))
      ++cur;
    int d = c[cur] > 0 ? 1 : -1;
    pr1(cur);
    pr2(d);
    a[cur] += d;
    a[cur + 1] += d;
    c[cur] -= d;
    cur = max(cur - 1, p);
  }
}
int main() {
  solve();
  return 0;
}
