foo.cc: In function 'int main()':
foo.cc:8:19: error: 'pow' was not declared in this scope
  cout<<(a*d-b*c)%(pow(10,9)+7);
                   ^~~
foo.cc:8:19: note: suggested alternative: 'putw'
  cout<<(a*d-b*c)%(pow(10,9)+7);
                   ^~~
                   putw

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