View Compilation Error

0_0_33633210_20149.cpp: In function 'int dfs(int, int)':
0_0_33633210_20149.cpp:15:11: error: 'n' was not declared in this scope
     if(u==n+1) return 0;
           ^
0_0_33633210_20149.cpp:17:11: error: too few arguments to function 'int dfs(int, int)'
     l=dfs()
           ^
0_0_33633210_20149.cpp:14:5: note: declared here
 int dfs(int u,int t){
     ^
0_0_33633210_20149.cpp: In function 'void solve()':
0_0_33633210_20149.cpp:22:13: error: 'n' was not declared in this scope
     rep(i,1,n+1) cin>>a[i].fi>>a[i].se;
             ^
0_0_33633210_20149.cpp:3:34: note: in definition of macro 'rep'
 #define rep(i,a,n) for(int i=a;i<n;i++)
                                  ^
0_0_33633210_20149.cpp:22:28: error: 'pii' has no member named 'fi'
     rep(i,1,n+1) cin>>a[i].fi>>a[i].se;
                            ^
0_0_33633210_20149.cpp:22:37: error: 'pii' has no member named 'se'
     rep(i,1,n+1) cin>>a[i].fi>>a[i].se;
                                     ^