View Compilation Error

0_0_33313261_29891.cpp: In function 'void solve()':
0_0_33313261_29891.cpp:44:22: error: 'flag' was not declared in this scope
  if(n < m) swap(n,m),flag = 1;
                      ^
0_0_33313261_29891.cpp:48:6: error: 'flag' was not declared in this scope
   if(flag) swap(x,y);
      ^