View Compilation Error

24571_0_3947.cpp: In function `int main()':
24571_0_3947.cpp:9: error: `cin' undeclared (first use this function)
24571_0_3947.cpp:9: error: (Each undeclared identifier is reported only once for each function it appears in.)
24571_0_3947.cpp:13: error: `cout' undeclared (first use this function)
24571_0_3947.cpp:17: error: `OK' undeclared (first use this function)
4549_