#include <bits/stdc++.h>

using namespace std;

int o[4],a,b,c;
int place[1000002][4];
int n;

int main(){
    scanf("%d%d%d",&o[1],&o[2],&o[3]);
    a=o[1]>o[2]?(o[1]>o[3]?1:3):(o[2]>o[3]?2:3);
    b=o[a%3+1]>o[(a+1)%3+1]?a%3+1:(a+1)%3+1;
    c=6-a-b;
    if(o[a]>o[b]*o[c]){
        printf("-1");
        return 0;
    }
    for(int i=0;i<o[c];i++) place[++n][4-c]=i,place[n][4-b]=i;
    for(int i=n;i<o[b];i++) place[++n][4-c]=i,place[n][4-b]=o[c]-1;
    for(int i=1;n<o[a];i++) place[++n][4-c]=i;
    printf("%d\n",n);
    for(int i=1;i<=n;i++)   printf("%d %d %d\n",place[i][1],place[i][2],place[i][3]);
    return 0;
}