/in/foo.cc: In function 'void dfs(int, int, int)':
/in/foo.cc:47:17: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
         if((1<<i-1)&chos)continue;
                ~^~
/in/foo.cc:49:27: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
         dfs(x+1,chos|(1<<i-1),s+C[n-1][x-1]*i);
                          ~^~