#include<bits/stdc++.h>

using namespace std;

void _()
{
    int n, x, y;
    cin >> n >> x >> y;
    if(n == 1)
    {
        if(x == y)
        {
            cout << "1\n"<<x <<":"<<y<<"\n";
        }
        else
        {
            cout << "0\n"<<x<<":"<<y<<"\n";
        }
    }
    else
    {
        if(x+y >= n)
        {
            cout << 0 << "\n";
            int gmcnt = 0;
            while(gmcnt < n-2)
            {
                gmcnt++;
                if(x > 0)
                {
                    cout << "1:0\n";
                    x--;
                }
                else
                {
                    cout << "0:1\n";
                    y--;
                }
            }
            if(x == 0)
            {
                cout << "0:1\n0:"<<y-1<<endl;
            }
            else if(y == 0)
            {
                cout << "1:0\n";
                x--;
                cout << x << ":"<<0<<endl;
            }
            else
            {
                cout << x << ":0"<<endl;
                cout << "0:"<<y<<endl;
            }
        }
        else
        {
            cout << n-x-y<<endl;
            while(n > 0)
            {
                n--;
                if(x > 0)
                {
                    cout << "1:0\n";
                    x--;
                }
                else if(y>0)
                {
                    cout << "0:1\n";
                    y--;
                }
                else
                {
                    cout << "0:0\n";
                }
            }
        }
    }
    
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    
    int t = 1;
    //cin >> t;
    while(t--) _();
}