#include <iostream> using namespace std; int main() { int a,b,z,count=0; cin>>a>>b; for(int i=0;i<b;i=i+1){ cin>>z; count=count+z; } for(int j=2;j<a;j++){ cin>>z; count=count+z; for(int k=2;k<b;k=k+1){ count=count-z; } } for(int i=0;i<b;i=i+1){ cin>>z; count=count+z; } cout<<count; return 0; }