#include <iostream>
using namespace std;
int main()
{
int n;
cin>>n;
int ar[5005],fq[4]={0};
for(int i=0; i<n ; i++){
cin>>ar[i];
fq[ar[i]]++;
}
fq[0]=6;
int min=fq[0];
for(int i=0; i<4 ; i++){
if(fq[i]<min)
min=fq[i];
}
cout<<min<<"\n";
for(int j=0; j<min ; j++){
int x=0,y=0,z=0;
for(int i=1; i<=n; i++){
if(ar[i-1]==1 && x==0 )
{
x=i;
ar[i-1]=0;}
else if(ar[i-1]==2 && y==0 ){
y=i;
ar[i-1]=0;
}
else if(ar[i-1]==3 && z==0 ){
z=i;
ar[i-1]=0;}
/*if(z>0 && y>0 && x>0)
break;
*/}
cout<<x<<" "<<y<<" "<<z;
cout<<"\n";
}
return 0;
}
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