View Compilation Error

0_0_18884456_23057.cpp: In function 'void unionset(int, int)':
0_0_18884456_23057.cpp:40:17: error: 'u' was not declared in this scope
     else father[u]=v;
                 ^
0_0_18884456_23057.cpp:40:20: error: 'v' was not declared in this scope
     else father[u]=v;
                    ^