/in/foo.cc: In function 'int solve()':
/in/foo.cc:8:17: error: 'n' was not declared in this scope
  for(int i=2;i<=n;i++)
                 ^
/in/foo.cc:10:11: error: 'l' was not declared in this scope
   int now=l[i-1]+l[i-2];
           ^
/in/foo.cc:11:8: error: 'a' was not declared in this scope
   l[i]=a[i-1]-now;
        ^
/in/foo.cc:17:5: error: 'l' was not declared in this scope
  if(l[n]+l[n-1]!=a[n]){
     ^
/in/foo.cc:17:7: error: 'n' was not declared in this scope
  if(l[n]+l[n-1]!=a[n]){
       ^
/in/foo.cc:17:18: error: 'a' was not declared in this scope
  if(l[n]+l[n-1]!=a[n]){
                  ^