foo.cc:23:39: warning: bad option '-fwhole-program' to pragma 'optimize' [-Wpragmas]
 #pragma GCC optimize("-fwhole-program")
                                       ^
foo.cc:32:41: warning: bad option '-fcse-skip-blocks' to pragma 'optimize' [-Wpragmas]
 #pragma GCC optimize("-fcse-skip-blocks")
                                         ^
foo.cc:46:51: warning: bad option '-funsafe-loop-optimizations' to pragma 'optimize' [-Wpragmas]
 #pragma GCC optimize("-funsafe-loop-optimizations")
                                                   ^
foo.cc:55:10: warning: bad option '-fwhole-program' to attribute 'optimize' [-Wattributes]
 int main()
          ^
foo.cc:55:10: warning: bad option '-fcse-skip-blocks' to attribute 'optimize' [-Wattributes]
foo.cc:55:10: warning: bad option '-funsafe-loop-optimizations' to attribute 'optimize' [-Wattributes]
foo.cc: In function 'int main()':
foo.cc:61:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d%s",&u,&v,s);
         ~~~~~^~~~~~~~~~~~~~~~~~

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