foo.cc: In function 'int main()':
foo.cc:16:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   16 | freopen("1243.in","r",stdin);freopen("1243.out","w",stdout);
      | ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
foo.cc:16:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   16 | freopen("1243.in","r",stdin);freopen("1243.out","w",stdout);
      |                              ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
foo.cc:17:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   17 | scanf("%d%d%d%d",&m,&n,&cost,&L);
      | ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:19:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   19 | for(int j=1;j<=m;j++) scanf("%d",&sum[i][j]),sum[i][j]+=sum[i][j-1];
      |                       ~~~~~^~~~~~~~~~~~~~~~~

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