View Compilation Error

0_0_14688048_9640.cpp: In function 'void dfs(int)':
0_0_14688048_9640.cpp:55:25: error: 'struct std::pair<int, int>' has no member named 'size'
     for (int i=0;i<G[x].size();i++)
                         ^
0_0_14688048_9640.cpp:57:24: error: no match for 'operator[]' (operand types are 'std::pair<int, int>' and 'int')
         if (!Visit[G[x][i]])
                        ^
0_0_14688048_9640.cpp:59:21: error: no match for 'operator[]' (operand types are 'std::pair<int, int>' and 'int')
             dfs(G[x][i]);
                     ^