View Compilation Error

0_0_22187363_2528.cpp: In function 'int main()':
0_0_22187363_2528.cpp:24:35: error: 'scanf' was not declared in this scope
     while(scanf("%I64d%I64d",&n,&m)!=EOF)
                                   ^
0_0_22187363_2528.cpp:24:38: error: 'EOF' was not declared in this scope
     while(scanf("%I64d%I64d",&n,&m)!=EOF)
                                      ^
0_0_22187363_2528.cpp:53:29: error: 'printf' was not declared in this scope
         printf("%I64d\n",ans);
                             ^