foo.cc: In function 'int main()':
foo.cc:69:16: warning: left operand of comma operator has no effect [-Wunused-value]
   69 |  PolyList ans=(a, b, n);
      |                ^
foo.cc:69:22: warning: right operand of comma operator has no effect [-Wunused-value]
   69 |  PolyList ans=(a, b, n);
      |                      ^
foo.cc:69:20: error: conversion from 'int' to non-scalar type 'PolyList' requested
   69 |  PolyList ans=(a, b, n);
      |               ~~~~~^~~~

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