foo.cc: In function 'void build()':
foo.cc:23:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d%d%d%d",&n,&m,&TIME,&MONEY);
 ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:26:6: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 scanf("%d%d%d%d",&u,&v,&T,&M);
 ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:62:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
 freopen("in.txt","r",stdin);
 ~~~~~~~^~~~~~~~~~~~~~~~~~~~

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