foo.cc: In function 'void init()':
foo.cc:30:24: error: 'j' was not declared in this scope
   30 |             cin>>st[i][j];
      |                        ^
foo.cc:26:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   26 |     scanf("%d%d",&n,&m);
      |     ~~~~~^~~~~~~~~~~~~~

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