foo.cc: In function 'int main()':
foo.cc:19:20: error: 'i' was not declared in this scope
             if(s[a[i]]==0){
                    ^
foo.cc:9:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&N);
     ~~~~~^~~~~~~~~
foo.cc:11:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d",&a[i]);
         ~~~~~^~~~~~~~~~~~
foo.cc:13:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&M);
     ~~~~~^~~~~~~~~
foo.cc:15:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&l,&r);
         ~~~~~^~~~~~~~~~~~~~

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