foo.cpp: In function 'int main()':
foo.cpp:9:16: error: 'x' was not declared in this scope
  scanf("%d%d",&x,&y);
                ^
foo.cpp:9:19: error: 'y' was not declared in this scope
  scanf("%d%d",&x,&y);
                   ^
foo.cpp:6:12: warning: unused variable 'j' [-Wunused-variable]
  int n,m,i,j,s,t;
            ^