View Compilation Error

0_0_20288045_30755.cpp: In function 'int main()':
0_0_20288045_30755.cpp:3:23: error: 'n' was not declared in this scope
  while(scanf("%d %d",&n,&m) && n+m)
                       ^
0_0_20288045_30755.cpp:3:26: error: 'm' was not declared in this scope
  while(scanf("%d %d",&n,&m) && n+m)
                          ^
0_0_20288045_30755.cpp:3:27: error: 'scanf' was not declared in this scope
  while(scanf("%d %d",&n,&m) && n+m)
                           ^
0_0_20288045_30755.cpp:12:10: error: 'graph' was not declared in this scope
   memset(graph,0,sizeof(graph));
          ^
0_0_20288045_30755.cpp:12:31: error: 'memset' was not declared in this scope
   memset(graph,0,sizeof(graph));
                               ^
0_0_20288045_30755.cpp:30:28: error: 'printf' was not declared in this scope
   printf("%d\n",graph[1][n]);
                            ^