View Compilation Error

0_0_24450135_4136.cpp: In function 'void read()':
0_0_24450135_4136.cpp:36:22: error: 'O' was not declared in this scope
 rep(i, 0, 4) {rep(j, O, 13) printf("%d\n",a[i][j]);puts("");}
                      ^
0_0_24450135_4136.cpp:13:31: note: in definition of macro 'rep'
 #define rep(i,l,r) for(int i=(l);i<(r);++i)
                               ^