View Compilation Error

0_0_28853842_9244.cpp: In function 'int main()':
0_0_28853842_9244.cpp:66:2: error: 'lf' was not declared in this scope
  lf l,u,x;
  ^
0_0_28853842_9244.cpp:67:35: error: 'l' was not declared in this scope
  while(~scanf("%d%d%lf%lf",&n,&m,&l,&u))
                                   ^
0_0_28853842_9244.cpp:67:38: error: 'u' was not declared in this scope
  while(~scanf("%d%d%lf%lf",&n,&m,&l,&u))
                                      ^
0_0_28853842_9244.cpp:74:18: error: 'x' was not declared in this scope
     scanf("%lf",&x);
                  ^