cin >> K;
   cin >> m;

   // Initial array:   1 2 3 4 5 6 7 8 ... K
   for ( int i = 1; i <= K; i++ )
      a[i] = i;

   for ( int i = 1; i <= m; i++ )
   {
      cin >> skip;

      // Easy way (you can do it inside array a[ ] the hard way)
      copy a[i] to b[ ]; but omit a[skip], a[2*skip], ...;
      copy b[ ] back to a[ ]
   }
  

   int nLeft = K;       // number of friends left: a[1..nLeft]

   for ( int i = 1; i <= m; i++ )
   {
      cin >> skip;

      /* -------------------------------------------
         Copy not deleted friends in b[ ]
             [1] [2] ... [skip] [skip+1]
                          ^ skip
         ------------------------------------------- */
      to = 1;

      for ( from = 1; from <= nLeft; from++ )
          if ( from%skip != 0 )
              b[to++] = a[from];

      /* --------------------------------------
         Copy back to a[ ]
         -------------------------------------- */
      nLeft = to - 1;     // Note: to = #elements copied !
      for ( int j = 1; j <= nLeft; j++ )
         a[j] = b[j];
   }