#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); i++)
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<ll> vll;
typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<vector<ll>> vvll;
const ll inf = 1e16;
const ll md = 1000000007;

int main() {
  int ans=0;
  for(int m=1;m<=12;m++){
    for(int t=0;;t++){
      if(m-t>9) continue;
      if(m-t<0) break;
      int d=t*10+(m-t);
      if(m==2&&d>28) break; 
      else if((m==4||m==6||m==9||m==11)&&d>30) break; 
      else if(d>31) break; 
      ans++;
      cout<<m<<" "<<d<<endl;
    }
  }
  cout<<ans<<endl;
  return 0;
}