1 //2017-02-24
  2 #include <iostream>
  3 #include <cstdio>
  4 #include <cstring>
  5 #include <algorithm>
  6 
  7 using namespace std;
  8 
  9 struct node
 10 {
 11     int a, b, step, pre, op;
 12 }q[1000];
 13 
 14 int pots[3], POT[3], book[105][105];
 15 string option[10] = {"", "FILL(1)", "FILL(2)", "DROP(1)", "DROP(2)", "POUR(1,2)", "POUR(2,1)"};
 16 
 17 void fill(int i)
 18 {
 19     pots[i] = POT[i];
 20 }
 21 
 22 void drop(int i)
 23 {
 24     pots[i] = 0;
 25 }
 26 
 27 void pour(int i, int j)
 28 {
 29     if(pots[i] > POT[j]-pots[j]){
 30         pots[i] -= (POT[j]-pots[j]);
 31         pots[j] = POT[j];
 32     }else{
 33         pots[j] += pots[i];
 34         pots[i] = 0;
 35     }
 36 }
 37 
 38 void init(int a, int b)
 39 {
 40     pots[1] = a;
 41     pots[2] = b;
 42 }
 43 
 44 void push(int pos, int a, int b, int step, int pre, int op)
 45 {
 46     q[pos].a = a;
 47     q[pos].b = b;
 48     q[pos].step = step;
 49     q[pos].pre = pre;
 50     q[pos].op = op;
 51 }
 52 
 53 void print(int pos)
 54 {
 55     if(q[pos].pre == -1)return;
 56     print(q[pos].pre);
 57     cout<<option[q[pos].op]<<endl;
 58 }
 59 
 60 int min(int a, int b)
 61 {
 62     return a < b ? a : b;
 63 }
 64 
 65 int main()
 66 {
 67     int C, a, b, step;
 68     while(cin>>POT[1]>>POT[2]>>C)
 69     {
 70         int head = 0, tail = 1;
 71         q[0].a = 0;
 72         q[0].b = 0;
 73         q[0].step = 0;
 74         q[0].pre = -1;
 75         memset(book, 0, sizeof(book));
 76         book[0][0] = 1;
 77         while(head < tail)
 78         {
 79             a = q[head].a;
 80             b = q[head].b;
 81             step = q[head].step;
 82 
 83             if(a==C || b==C){
 84                 cout<<step<<endl;
 85                 print(head);
 86                 break;
 87             }
 88 
 89             init(a, b);
 90             fill(1);
 91             if(!book[pots[1]][pots[2]]){
 92                 book[pots[1]][pots[2]] = 1;
 93                 push(tail, pots[1], pots[2], step+1, head, 1);
 94                 tail++;
 95             }
 96 
 97             init(a, b);
 98             fill(2);
 99             if(!book[pots[1]][pots[2]]){
100                 book[pots[1]][pots[2]] = 1;
101                 push(tail, pots[1], pots[2], step+1, head, 2);
102                 tail++;
103             }
104 
105             if(a>0){
106                 init(a, b);
107                 drop(1);
108                 if(!book[pots[1]][pots[2]]){
109                     book[pots[1]][pots[2]] = 1;
110                     push(tail, pots[1], pots[2], step+1, head, 3);
111                     tail++;
112                 }
113             }
114 
115             if(b>0){
116                 init(a, b);
117                 drop(2);
118                 if(!book[pots[1]][pots[2]]){
119                     book[pots[1]][pots[2]] = 1;
120                     push(tail, pots[1], pots[2], step+1, head, 4);
121                     tail++;
122                 }
123             }
124 
125             init(a, b);
126             pour(1, 2);
127             if(!book[pots[1]][pots[2]]){
128                 book[pots[1]][pots[2]] = 1;
129                 push(tail, pots[1], pots[2], step+1, head, 5);
130                 tail++;
131             }
132 
133             init(a, b);
134             pour(2, 1);
135             if(!book[pots[1]][pots[2]]){
136                 book[pots[1]][pots[2]] = 1;
137                 push(tail, pots[1], pots[2], step+1, head, 6);
138                 tail++;
139             }
140 
141             head++;
142         }
143         if(head>=tail)cout<<"impossible"<<endl;
144     }
145     return 0;
146 }