View Compilation Error

0_0_10188332_9847.cpp: In function `void Union(int, int)':
0_0_10188332_9847.cpp:21: error: `R1' undeclared (first use this function)
0_0_10188332_9847.cpp:21: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_10188332_9847.cpp:21: error: `R2' undeclared (first use this function)
0_0_10188332_9847.cpp: In function `int main()':
0_0_10188332_9847.cpp:31: error: `p1' undeclared (first use this function)
0_0_10188332_9847.cpp:31: error: `p2' undeclared (first use this function)