foo.cpp:1:1: error: 'include' does not name a type
 include <iostream> 
 ^
foo.cpp: In function 'int main()':
foo.cpp:8:19: error: 'scanf' was not declared in this scope
 scanf("%d%d",&n,&m);
                   ^
foo.cpp:32:16: error: 'printf' was not declared in this scope
 printf("%d",ans);
                ^