foo.cc: In function 'void build(int, int, int)':
foo.cc:44:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int mid=l+r>>1; build(ls,l,mid); build(rs,mid+1,r); pushup(p);
          ~^~
foo.cc: In function 'void change_add(int, int, int, int)':
foo.cc:48:29: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int L=t[p].l,R=t[p].r,mid=L+R>>1;
                            ~^~
foo.cc: In function 'void change_rev(int, int, int)':
foo.cc:57:29: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int L=t[p].l,R=t[p].r,mid=L+R>>1;
                            ~^~
foo.cc: In function 'tree ask(int, int, int)':
foo.cc:66:29: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int L=t[p].l,R=t[p].r,mid=L+R>>1;
                            ~^~
foo.cc: In function 'int main()':
foo.cc:84:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&q);
  ~~~~~^~~~~~~~~~~~~~
foo.cc:90:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(int i=1;i<=n;++i) {scanf("%d",a+i);a[i]=(a[i]%mod+mod)%mod;}
                         ~~~~~^~~~~~~~~~
foo.cc:95:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%s",op);
   ~~~~~^~~~~~~~~
foo.cc:96:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&l,&r);
   ~~~~~^~~~~~~~~~~~~~
foo.cc:97:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   if(op[0]=='I'){scanf("%d",&x);change_add(1,l,r,x);}
                  ~~~~~^~~~~~~~~
foo.cc:99:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   else {scanf("%d",&x);printf("%d\n",ask(1,l,r).f[x]);}
         ~~~~~^~~~~~~~~

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