View Compilation Error

0_0_29704622_30370.cpp:2:3: error: expected unqualified-id before 'while'
   while (bfs()) ans += dfs(S, INF);
   ^
0_0_29704622_30370.cpp:3:3: error: expected unqualified-id before 'return'
   return ans;
   ^
0_0_29704622_30370.cpp:4:1: error: expected declaration before '}' token
 }
 ^