1 #include <iostream>
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <cstdlib>
  5 #include <algorithm>
  6 #include <utility>
  7 #include <queue>
  8 #include <stack>
  9 #include <vector>
 10
 11 using namespace std;
 12
 13 int n, sa, sb, m;
 14
 15 //sap by kuangbin
 16 const int MAXN = 100010;//点数的最大值
 17 const int MAXM = 400010;//边数的最大值
 18 const int INF = 0x3f3f3f3f;
 19 struct Edge
 20 {
 21     int to,next,cap,flow;
 22 } edge[MAXM]; //注意是MAXM
 23 int tol;
 24 int head[MAXN];
 25 int gap[MAXN],dep[MAXN],cur[MAXN];
 26 void init()
 27 {
 28     tol = 0;
 29     memset(head,-1,sizeof(head));
 30 }
 31 void addedge(int u,int v,int w,int rw = 0)
 32 {
 33     edge[tol].to = v;
 34     edge[tol].cap = w;
 35     edge[tol].flow = 0;
 36     edge[tol].next = head[u];
 37     head[u] = tol++;
 38     edge[tol].to = u;
 39     edge[tol].cap = rw;
 40     edge[tol].flow = 0;
 41     edge[tol].next = head[v];
 42     head[v] = tol++;
 43 }
 44 int Q[MAXN];
 45 void BFS(int start,int end)
 46 {
 47     memset(dep,-1,sizeof(dep));
 48     memset(gap,0,sizeof(gap));
 49     gap[0] = 1;
 50     int front = 0, rear = 0;
 51     dep[end] = 0;
 52     Q[rear++] = end;
 53     while(front != rear)
 54     {
 55         int u = Q[front++];
 56         for(int i = head[u]; i != -1; i = edge[i].next)
 57         {
 58             int v = edge[i].to;
 59             if(dep[v] != -1)continue;
 60             Q[rear++] = v;
 61             dep[v] = dep[u] + 1;
 62             gap[dep[v]]++;
 63         }
 64     }
 65 }
 66 int S[MAXN];
 67 int sap(int start,int end,int N)
 68 {
 69     BFS(start,end);
 70     memcpy(cur,head,sizeof(head));
 71     int top = 0;
 72     int u = start;
 73     int ans = 0;
 74     while(dep[start] < N)
 75     {
 76         if(u == end)
 77         {
 78             int Min = INF;
 79             int inser;
 80             for(int i = 0; i < top; i++)
 81                 if(Min > edge[S[i]].cap - edge[S[i]].flow)
 82                 {
 83                     Min = edge[S[i]].cap - edge[S[i]].flow;
 84                     inser = i;
 85                 }
 86             for(int i = 0; i < top; i++)
 87             {
 88                 edge[S[i]].flow += Min;
 89                 edge[S[i]^1].flow -= Min;
 90             }
 91             ans += Min;
 92             top = inser;
 93             u = edge[S[top]^1].to;
 94             continue;
 95         }
 96         bool flag = false;
 97         int v;
 98         for(int i = cur[u]; i != -1; i = edge[i].next)
 99         {
100             v = edge[i].to;
101             if(edge[i].cap - edge[i].flow && dep[v]+1 == dep[u])
102             {
103
104                 flag = true;
105                 cur[u] = i;
106                 break;
107             }
108         }
109         if(flag)
110         {
111             S[top++] = cur[u];
112             u = v;
113             continue;
114         }
115         int Min = N;
116         for(int i = head[u]; i != -1; i = edge[i].next)
117             if(edge[i].cap - edge[i].flow && dep[edge[i].to] < Min)
118             {
119                 Min = dep[edge[i].to];
120                 cur[u] = i;
121             }
122         gap[dep[u]]--;
123         if(!gap[dep[u]])return ans;
124         dep[u] = Min + 1;
125         gap[dep[u]]++;
126         if(u != start)u = edge[S[--top]^1].to;
127     }
128     return ans;
129 }
130
131 inline int ch(int x, int y, int isout){return (isout?(x*sb+y):(x*sb+y+sa*sb));}
132 void buildmap()
133 {
134     init();
135     n = sa*sb*2+2;
136     for(int i=1; i<=sa; i++)
137     for(int j=1; j<=sb; j++)
138     addedge(ch(i,j,0), ch(i,j,1),1);
139     for(int i=1; i<=sa; i++)
140     {
141         for(int j=1; j<sb; j++)
142         {
143             addedge(ch(i,j,1), ch(i,j+1,0), 1);
144             addedge(ch(i,j+1,1), ch(i,j,0), 1);
145         }
146     }
147     for(int i=1; i<sa; i++)
148     {
149         for(int j=1; j<=sb; j++)
150         {
151             addedge(ch(i,j,1), ch(i+1,j,0), 1);
152             addedge(ch(i+1,j,1), ch(i,j,0), 1);
153         }
154     }
155     for(int i=1; i<=sb; i++)
156     {
157         addedge(ch(1,i,1), n-1, 1);
158         addedge(ch(sa,i,1), n-1, 1);
159     }
160     for(int i=2; i<sa; i++)
161     {
162         addedge(ch(i,1,1), n-1, 1);
163         addedge(ch(i,sb,1), n-1, 1);
164     }
165 }
166
167 int main()
168 {
169 //    freopen("in.txt", "r", stdin);
170
171     int T, a, b;
172     scanf("%d", &T);
173     while(T--)
174     {
175         scanf("%d%d%d", &sa, &sb, &m);
176         buildmap();
177         for(int i=0; i<m; i++)
178         {
179             scanf("%d%d", &a, &b);
180             addedge(0, ch(a,b,0), 1);
181         }
182         int ans = sap(0,n-1, n);
183         if(ans==m)printf("possible\n");
184         else printf("not possible\n");
185     }
186     return 0;
187 }