#include<bits/stdc++.h>
using namespace std;
int i,j=1,k=2,a[3];
vector <pair<int,int> > ans;
void calc(int x,int y){
	if(a[x]>a[y]) swap(x,y);
	ans.push_back({y,x}),a[y]-=a[x],a[x]*=2;
}
int main(){
	scanf("%d%d%d",&a[0],&a[1],&a[2]);
	while(a[0]&&a[1]&&a[2]){
		if(a[i]>a[j]) swap(i,j);
		if(a[i]>a[k]) swap(i,k);
		if(a[j]>a[k]) swap(j,k);
		for(int v=a[j]%a[i]>a[i]/2?(a[j]-1)/a[i]+1:a[j]/a[i];v;v>>=1) calc(i,v&1?j:k);
	}
	printf("%d\n",ans.size());
	for(auto i:ans) printf("%d %d\n",i.first+1,i.second+1);
	return 0;
}