/in/foo.cc: In function 'int main()':
/in/foo.cc:20:11: warning: array subscript is above array bounds [-Warray-bounds]
    a1[z][2]=1;
    ~~~~~~~^
/in/foo.cc:25:14: warning: array subscript is above array bounds [-Warray-bounds]
    a1[z-1][2]+=1;
    ~~~~~~~~~~^~~
/in/foo.cc:25:14: warning: array subscript is above array bounds [-Warray-bounds]
/in/foo.cc:31:13: warning: array subscript is above array bounds [-Warray-bounds]
   if(a1[i][2]!=0)
      ~~~~~~~^
/in/foo.cc:33:32: warning: array subscript is above array bounds [-Warray-bounds]
    cout<<a1[i][1]<<" "<<a1[i][2]<<endl;
                                ^