#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define per(i,a,b) for(int i=(a);i>=(b);i--)
#define fi first
#define se second
#define eb emplace_back
#define bp __builtin_parity
#define y1 yyl
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<pii> vp;

int read() {
	int x=0,w=1; char c=getchar();
	while(!isdigit(c)) {if(c=='-') w=-1; c=getchar();}
	while(isdigit(c)) {x=x*10+c-'0'; c=getchar();}
	return x*w;
}

int n,a,b,f[109][1009][1009],vst[109][1009][1009];

int dfs(int x,int a,int b) {
	if(a<0) return n+1; if(b<0) return n+1;
	if(x==1) {
		if(a==b) return f[x][a][b]=1;
		else return f[x][a][b]=0;
	}
	if(vst[x][a][b]) return f[x][a][b]; vst[x][a][b]=1;
	f[x][a][b]=min(dfs(x-1,a-1,b),min(dfs(x-1,a,b-1),dfs(x-1,a,b)+1));
	return f[x][a][b];
}
void print(int x,int a,int b) {
	if(x==1) {
		printf("%d:%d\n",a,b); return;
	}
	if(a&&f[x-1][a-1][b]==f[x][a][b]) {
		printf("%d:%d\n",1,0), print(x-1,a-1,b);
	} else if(b&&f[x-1][a][b-1]==f[x][a][b]) {
		printf("%d:%d\n",0,1), print(x-1,a,b-1);
	} else {
		printf("%d:%d\n",0,0), print(x-1,a,b);
	}
}

signed main() {
	n=read(), a=read(), b=read();
	dfs(n,a,b);
	printf("%d\n",f[n][a][b]);
	print(n,a,b);
	return 0;
}